A GUIDE 



TO THE 



Dissection of the Blood Vessels 

and Nerves 



OF THE 



Pectoral and Pelvic 

Limbs 



OF 



The Horse 



BY 



Grant Sherman Hopkins, 

New York State Veterinary College at Cornell University, 
Ithaca, N. Y. 



A GUIDE 



TO THE 



Dissection of the Blood Vessels 
and Nerves 



OF THE 



Pectoral and Pelvic 

Limbs 



OF 



The Horse 



BY 

Grant Sherman Hopkins, 

New York State Veterinary College at Cornell University, 

Ithaca, N. Y. 



COPYRIGHT 1 9 14 
BY GRANT SHERMAN HOPKINS 






©CI.Aa89109 

OCT 29 1914 



PREFACE 

Every teacher who has had experience with classes in Anatomy appre- 
ciates the diffictilties that confront the student in his attempt to dissect 
any portion of the body with only his text-book of Descriptive Anatomy, 
for a guide. The present "Guide" has been prepared in the hope of assist- 
ing students in the dissection of the blood-vessels and nerves of the pec- 
toral and pelvic limbs. A knowledge of the muscles is presupposed. In 
our experience, we have found it most desirable that, upon the completion 
of a part, the student should demonstrate his dissection to the instructor 
in charge. By no other means can the .student be brought to realize 
more clearly the vast difference between studying and knowing the actual 
object itself and the mere memorizing the description of it as given in 

his text-book. . 

G. S. H. 



Dissection of the Blood-Vessels and Nerves of 
the Arm or Pectoral Limb 

Cut the skin along the median Une from the xiphoid cartilage to a point 
15 or 20 cm. cephalad of the presternum; also cut at a right angle to this 
along the middle of the proximal half of the antebrachivini and reflect the 
skin from the pectoral muscles. Note the large vein (V. cephalica) and the 
small artery lying in the groove formed by the anterior superficial pectoral 
muscle and the adjoining border of the M. mastoido-himieralis. Transect 
the two superficial pectorals close to their sternal attachments. Now 
dissect up the cervical panniculus, transect it a short distance from its 
attachment to the sternum and turn it aside. Beneath this portion 
of the pannicvilus is a mass of fatty tissue in which are numerous lymph 
nodules — the Prescapular or superficial cervercal lymph gland. The full 
extent of this gland may be seen when the M. mastoido-humeralis is turned 
aside. Transect the mastoido-hiuneralis a little above (cephalad) the 
point of the shoulder and turn it aside sufficiently to expose the underlying 
prescapular portion of the anterior deep pectoral muscle and the prescapvdar 
lymph gland. Do not disturb unnecessarily the gland for beneath it 
are an artery and vein of some surgical importance. Trace the large 
vein (V. cephalica) and the small artery (a branch of the A. cervicalis 
inferior) that cross the anterior deep pectoral muscle in the groove between 
this muscle and the mastoido-hiuneralis, in so far as the vessels are at 
present accessible. Ligate and cut the vessels. Abduct the arm somewhat 
and identify the two deep pectoral muscles. Transect the latter muscles close 
to their attachment to the sternum. Abduct the arm a little and dissect 
between the deep pectoral muscles and the thoracic wall until the large A. 
and V. Axillaris are exposed. Carefully clean up the V. Axillaris noting 
meantime the lymph glands, Posterior cervical or prepectoral, that lie 
just cephalad or anterior to the V. Axillaris. Cut the vein in order clearly 
to expose the A. Axillaris which lies immediately dorsal to it. Clean up 
the A. Axillaris taking care not to cvit any of its branches or the nerves that 
cross the ventral surface of the artery a short distance (4 to 6 cm.) from the 
first rib. Cut the artery close to the rib. Occasionally a large vein lies 
just anterior to the A. Axillaris; if so, this also should be cut. 

A. cervicalis inferior arises from the axillaris nearly opposite the first rib. 
Near the ventral border of the M. scalenus it divides into two nearly equal 
branches — a ventral and a dorsal branch. The ventral branch crosses 



the superficial surface of the anterior deep pectoral and then runs in the 
groove formed by this muscle and the mastoido-humeralis, as already seen, 
and terminates in the mastoido-himieralis. Small branches are supplied 
to the posterior cervical lymph glands, the cervical pannicultis, the stemo- 
mandibularis, sterno-thyrohyoideus, anterior superficial pectoral and a 
small branch to the region of the presterntun. The dorsal branch extends 
antero-dorsally along the anterior border of the anterior deep pectoral 
muscle. It passes beneath the prescapular lymph gland and between the 
muscles subscapulo-hyoideus and mastoido-htomeralis to the latter of which 
it is principally distributed. It also gives off branches to the anterior 
deep pectoral muscle and to the posterior cervical and prescapular lymph 
glands. 

The ventral portion of the M. scalenus intervenes between the axillary 
blood-vessels and the nerves that form the brachial plexus. The brachial 
plexus is formed by the ventral divisions of the 6th, 7th and 8th, cervical 
and the ist and 2d thoracic nerves, as will be demonstrated later. Cut 
the dorsal branch of the A. cervicalis inferior and carefully remove the 
connective tissue that surroimds the large nerve trtmks of the brachial 
plexus. 

N. phrenicus or diaphragmatic nerve originates from the ventral divisions 
of the 6th and 7th cervical nerves ; occasionally it receives a small branch 
from the 5th cervical also. The two or three radicals of the phrenic 
nerve extend obliquely across the superficial face of the M. scalenus and at 
its ventral border unite to form a single trunk, just as the nerve enters the 
thorax, or a short distance within the thoracic cavity. Dissect up from the 
surface of the scalenus the two or three radicals of the N. phrenicus. Im- 
mediately after crossing the A. cervicalis inferior the N. phrenicus receives 
a small communicating branch from the inferior cervical ganglion of the 
sympathetic nerve. The course of the phrenic nerve through the thoracic 
cavity to the diaphragm will be studied when the thoracic portion, of the 
vagus and sympathetic nerves are traced. 

Exposure of the brachial plexus and removal of the thoracic limb. 

Expose as follows, the ventral divisions of the nerves that form the 
brachial plexus, viz., the 6th (not constant), 7th and 8th cervical and the 
I St and 2d thoracic. Cut the N. phrenicus at the first rib. Remove a 
section of the ventral portion of the M. scalenus opposite the 6th, 7th, and 
8th intervertebral foramina. Cut the skin and the Mm. panniculus 
and latissimus, some distance (30 to 50 cm.) posterior to the scapula; cut 
the skin and both portions of the trapezius close to the ligamentum nuchae; 



also cut the serratus magnus, and rhomboideus close to their attach- 
ments to the scapula thus leaving the arm attached to the body only by 
the nerves of the brachial plexus. Before attempting to expose farther the 
ventral divisions of the 6th, if present, 7th and 8th cervical and the 
1st and 2d thoracic nerves, first note on a skeleton the relation of the first 
two ribs to the 6th, 7th and 8th cervical and the ist and 2d thoracic inter- 
vertebral foramina, through which the above mentioned nerves emerge from 
the spinal cord. Now place the arm in such a position that the whole of 
the thoracic portion of the M. serratus magnus is exposed. Carefully 
remove the small portion of the M. scalenus that lies dorsal to the brachial 
plexus taking care not to cut any of the nerves. The large nerve to the 
thoracic portion of the serratus magnus arises from the 7th and 8th cervi- 
cals (or from the 8th only) and extends posteriorly on the surface of the 
serratus magnus to which it is distributed. This nerve, more or less covered 
by connective tissue, may emerge from between the dorsal and ventral 
portions of the scalenus, or it may pass through the small dorsal portion of 
the muscle. After tracing the nerve, cut it 15 to 20 cm. from its origin. 
The ventral divisions of the 7th and 8th cervical nerves are readily exposed ; 
the 1st and 2d thoracic nerves however, are covered by the ribs of which 
the first one must be cut in order to expose the nerves. Remove enough 
of the serratus magnus to expose the first rib. Cut the rib a little ventral 
to the A. Axillaris, also cut it close to the tuberosity of the rib and remove 
the detached portion. The A. cervicalis inferior should now be traced to 
its place of origin from the A. Axillaris. With a little care the ventral 
divisions of the first two thoracic nerves may be found and cut close to 
the intervertebral foramina ; the 7th and- 8th cervical nerves also should 
be cut close to the vertebrae and the arm removed. 

Nn. pectorales. Before attempting to demonstrate the nerves to the 
pectoral muscles first carefidly remove the connective tissue and fat from 
the nerves of the brachial plexus using for this purpose the forceps, the back 
of the scalpel, or some other non cutting instrument. The origin of the 
pectoral nerves vary somewhat in different individuals. The following 
disposition however, is common. The most cephalic or anterior of the 
pectoral nerves originates from the 7th and 8th cervicals and is distributed 
wholly to the anterior deep pectoral muscle (PL I, 27). The nerve enters 
the muscle a little dorsal to the cephalic vein where it crosses the anterior 
deep pectoral. A communicating branch between this nerve and the 
phrenic is quite commonly present. The nerves to the superficial pectoral 
muscles arise from the loop or arch formed by the N. musculo-cutaneous 
(PL I, 29) and the N. medianus (PL I, 32) immediately beneath the A. axil- 



8 " 

laris and from the brachial plexus, in common with the N. medianus (PI. I, 
30, 31). Carefully dissect up the overlying posterior portion or sternal 
extremity of the anterior deep pectoral and trace the nerves to their respec- 
tive places of distribution in the superficial pectoral muscles. The two or 
more nerves to the posterior deep pectoral and the panniculus are readily 
found. They arise from the brachial plexus apparently in common with 
the Nn. medianus and ulnaris. The smaller and more anterior of the 
two nerves (in the present specimen) soon divides into three or four 
branches which enter the muscle near its humeral end along with the 
artery and vein supplied to the muscle. The larger and more posterior 
nerve also divides into several branches some of which are distributed to 
the posterior deep pectoral and some to the panniculus ; note particularly 
the large branch which accompanies the large V. thoracica externa which 
runs along the dorsal margin of the posterior deep pectoral and is continued 
posteriorly in the panniculus. 

A. suprascapularis arises from the A. axillaris near the anterior border of 
the tendon of the subscapularis, and close to the N. musculo-ctitaneous 
where it crosses the A. axillaris. About one centimeter from its origin 
the A. suprascapularis divides into two branches, of which one is distributed 
to the subscapularis, anterior deep pectoral and the supraspinatus ; the 
other branch is distributed to the anterior deep pectoral, supraspinatus, 
the shoulder joint, and the proximal tendon of the biceps. The artery is 
accompanied by the V. suprascapularis. 

N. suprascapularis (PI. I, 28; PL II, 21) originates from the 7th and 8th 
cervical nerves but principally from the 7th; occasionally some fibres 
originate from the 6th cervical nerve also. This large nerve passes between 
the adjacent borders of the supraspinatus and subscapularis. Carefully 
dissect the supraspinatus from the adjoining subscapularis, on one side 
of it, and the infraspinatus, on the other, and transect the muscle opposite 
the N. suprascapularis. Reflect the muscle sufficiently to expose the 
two or three large branches of the nerve to the supraspinatus, which branches 
are given off just as the nerve crosses the anterior border of the scapula. 
Trace the nerve across the supraspinus fossa and note its width, i to 2 cm. 
opposite the spine of the scapula. Just as the nerve enters the M. infra- 
spinatus it divides into 5 or 6 branches, all of which are distributed to this 
muscle. 

Nn. subscapulares (PI. I, 47). There are usually two or more of these 
nerves. They pass directly to the M. subscapularis but before reaching 
it they divide into numerous branches which diverge somewhat like the 
rays of a fan. 



The nerve to the M. latissimus arises from near the middle of the brachial 
plexus, most of its fibres coming from the 8th cervical (PI. I, 48). It 
passes obliquely across the deep face of the Mm. subscapularis and teres 
major and is distributed wholly to the latissimus. 

Nerves to the M. teres major {PI. I, 7). There are from i to 3 small nerves 
supplied to this muscle. They arise from the N. axillaris or rather are 
branches of it, and pass directly to the muscle, close to its anterior border. 

N. axillaris (PL I, 46) arises from the 7th and 8th cervical nerves. It 
passes through the triangular space formed by the Mm. subscapularis, 
teres major, and the caput longum tricipitis. To demonstrate the distri- 
bution of the nerve first remove the skin and the panniculus from the 
lateral or external surface of the scapidar region. Dissect up the borders 
of the M. deltoideus and transect it about 15 to 18 cm. from its attachment 
to the deltoid tuberosity. Carefully reflect the humeral portion of the 
muscle in order to expose the N. axillaris which enters the deep face of the 
muscle directly opposite the above mentioned triangular space (PI. II, 22). 
Beneath the muscle, the nerve divides into several branches which are 
distributed as follows: several branches enter the deltoideus; one large 
branch passes obliquely across the superficial surface of the teres minor 
(near its humeral end) to the anterior face of the brachium and enters the 
mastoido-humeralis several centimeters below (distal to) the point of the 
shoulder (PL I, 24); another large branch crosses the superficial surface 
of the caput laterale tricipitis or sometimes, is embedded in the substance 
of this muscle, and emerges from beneath the posterior border of the M. 
deltoideus at the level of the deltoid tuberosity where it becomes subcutane- 
ous (PL II, 23) ; from here, this subcutaneous branch extends to the antero- 
intemal aspect of the antebrachiiim where it breaks up into several cutaneous 
branches some of which extend nearly to the carpus. One branch of the 
N. axillaris is distributed to the teres minor. This branch may be readily 
demonstrated by transecting the muscle, a little proximal to the N. axillaris, 
and drawing aside the muscle. One or more branches are supplied to 
the teres major, one branch to the subscapularis and a very small filament 
to the M. capsularis. The branches to the subscapularis and the capsularis 
may arise from the main nerve trunk either separately or by a common 
branch. 

Clean up the V. axillaris and the several veins from the pectoral, pannicu- 
lus, and latissimus muscles also clean up the portion of the V. subscapularis 
that lies in the space between the Mm. subscapularis and teres major. 
Demonstrate the axillary lymph gland (PL I, 49), which lies on the tendon 



10 

of the teres major in the angle formed by the Vv. subscapularis and 
brachialis. Now slit the posterior superficial pectoral longitudinally near 
its middle. Turn aside the anterior portion of the muscle, together with 
the posterior deep pectoral, in order to expose the Mm. coraco-brachialis 
and the biceps brachii. 

N. musculo-cutaneous (PL I, 29, 29') is a large nerve and originates from the 
7th and 8th cervical nerves. Immediately after crossing the lateral face of 
the A. axillaris (PL I, 21) a large portion of the nerve joins the N. medianus 
by a large short branch that passes beneath the A. axillaris and with the 
N. medianus forms a loop around it. Occasionally this nerve loop is 
entirely wanting. From the loop thus formed, one or more branches are 
given ofi to the superficial pectoral muscles as already demonstrated. The 
larger portion of the N. musculo-cutaneous however, passes through the M. 
coraco-brachialis (PL I, 13, 29'), the overlying portion of which should be cut 
just proximal to the nerve, and drawn aside. As the nerve enters the 
coraco-brachialis it supplies a branch to it. Trace the main nerve through 
the coraco-brachialis to its termination in the biceps brachii near to the 
proximal end of the fleshy portion of the muscle (PL I, 29'). The connective 
tissue and aponeurosis covering the vessels and nerves on the medial face 
of the brachial region should now be removed. Note that here the vessels 
and nerves have the following relations, viz., the N. medianus lies most 
anteriorly and is followed in order by the A. brachialis, V. brachialis, N. 
ulnaris, and finally, in the proximal part of the brachium, the large N. 
radialis. Note also the small mass of lymph glands lying on the artery 
and vein near the distal third of the brachium (PL I, 49'). 

N. radialis (PL I, 40) lies posterior to the Nn. medianus and ulnaris and is 
the largest nerve of the brachial plexus. It originates from the 7th and 8th 
cervical and the ist thoracic nerves, but principally from the 8th cervical 
and I St thoracic. The nerve passes into the triangular space formed by 
the tendon of the teres major and latissimus, the caput longum tricipitis 
and the proximal end of the brachiahs. An artery and vein also enter this 
space and should be left intact. As the N. radialis enters the above men- 
tioned triangular space it gives off several branches which are distributed 
as follows: (a) one branch to the tensor fasciae antebrachii (PL I, 44). 
To demonstrate this branch, transect the tensor fasciae antebrachii near 
its distal third and turn the muscle aside but do not injure the nerve (a 
branch of the N. ulnaris) which runs along the anterior border (PL I, a), 
or sometimes crosses obliquely, the superficial surface of the distal 
half of the muscle. Sometimes a small communicating branch passes from 



II 

the N. ulnaris to this branch of the N. radiahs supphcd to the tensor fasciae 
antebrachii. (b) A large fasciculus composed of several branches, some 
of which recurve slightly around the tendon of the teres major and latis- 
simus; all the branches of this fasciculus are distributed to the caput 
longum tricipitis (PI. I, 41). (c) Branches to the caput laterale tricipitis, 
caput mediale tricipitis, and anconeus. Of these branches the small one 
to the caput mediale is readily found and traced to its muscle; the branches 
to the caput laterale and anconeus, however, are more or less completely 
hidden by the caput longum and caput laterale and often can be satis- 
factorily demonstrated only after the caput laterale has been dissected 
as follows: Turn aside the skin and the panniculus from the outer surface 
of the triceps. The posterior surface of the caput laterale may now be 
freely separated from the caput longum, but in dissecting up the anterior 
border of the muscle care should be taken not to cut the cutaneous nerve 
(a branch of the N. radialis) which emerges from beneath the muscle at, 
or close to, its anterior border (6 to 8 cm. distal to the cutaneous branch 
of the N. axillaris, or 8 to 10 cm. from the posterior edge of the M. deltoideus, 
PL II, c). Transect the caput laterale a little distal to its middle and 
freely reflect the distal portion of the muscle; the proximal portion of the 
muscle can be turned aside only a little distance as the nerve and blood- 
vessels to the muscle enter its deep or anterior face. Trace this nerve and 
also the cutaneous branch to their origin from the N.. radialis. Now trace 
the main trunk of the N. radialis in its course along the musculo-spiral groove 
to the point where it passes beneath the M. extensor carpi radialis at its 
origin, near the proximal end of the external epicondyle of the humerus 
(PL II, 1 1 , 25) . Remove the skin of the antebrachivim as far as to the carpus. 
Trace the cutaneous branches of the N. axillaris and the N. radalis, the 
former to the antero-internal side of the antebrachium and the latter to 
the antero-extemal side of the antebrachium. Both of these cutaneous 
branches may readily be traced to near the carpus. The M. extensor carpi 
radialis should now be dissected as follows: Transect it near the middle 
and freely turn aside the distal portion, but in turning aside the proximal 
part of the muscle care must be exercised to avoid cutting or breaking 
the nerves and blood-vessels that enter the deep face of the muscle (near 
the posterior border of the distal end of the M. brachialis). Now trace the 
N. radialis beneath the proximal portion of the extensor carpi radialis 
taking care not to cut the branches of this nerve, usually three in number, 
that enter the deep face of the muscle (PL II, d). The main nerve now 
passes beneath the extensor digitalis communis, near the origin of the 
muscle. Transect the extensor digitalis communis near the middle of the 
antebrachium and as the proximal portion is reflected avoid breaking the 



12 

blood-vessels and the two or three branches of the N. radialis supplied to 
the muscle (PI. II, e). Beneath this muscle the N. radialis gives off a small 
branch to the extensor carpi obliquus (PI. II, f) ; this branch lies directly upon 
the anterior-lateral face of the radius, at the side of the A. radialis anterior, 
and beneath the deep face of the extensor digitalis communis which must 
be turned aside sufficiently to expose the extensor carpi obliquus. Shortly 
before the N. radialis passes beneath the extensor digitalis lateralis, close 
to its origin, it gives off a small branch to this muscle (PL II, g). 
Slit open the aponeurotic sheath of the muscle and trace the branch some 
little distance. Now transect the muscle at the level of the N. radialis 
and trace the latter into the flexor carpi extemus where the nerve terminates 
(PL II, h). It will be seen from the above that the N. radialis supplies 
the following muscles; the triceps (caput longum, laterale and mediale), 
the tensor fasciae antebrachii, the anconeus, the extensor carpi radialis, 
the extensor digitalis communis, the extensor digitalis lateralis, the extensor 
carpi obliquus, and the flexor carpi externus, and one or more cutaneous 
branches to the skin of the antebrachium. 

Blood-vessels of the Brachial Region 

The large V. axillaris and several of the vessels opening into it, viz., 
V. thoracico-dorsalis from the deep pectoral muscles; the V. suprascapu- 
laris, the V. thoracico-externa together with the branches from the latissi- 
mus and panniculus that communicate with the V. thoracico-externa a 
short distance from its termination, have already been exposed. Additional 
veins should be noted as they are uncovered in the further dissection. 

A. axillaris (PL I, 21). Upon emerging from the thorax the A. axillaris 

crosses the tendon of origin of the coraco-brachialis and the insertion of 
the subscapularis, at the postero-internal side of the scapulo-humeral 
joint. From here the artey is continued by the A. brachialis (PL I, 23) 
which extends obliquely across the middle of the humerus to the antero- 
intemal side of the distal third of the shaft of the bone where it divides 
into two terminal branches — the A. radialis anterior and the A. radialis 
posterior. 

Branches of the A. axillaris, 

A. cervicalis inferior. 
A. suprascapularis. 
A. subscapularis. 
The A. cervicalis inferior and the suprascapularis have already been 
traced, pp. 5, 8. The large A. subscapularis (PL I, 22) arises from the 



13 

axillaris at the posterior border of the M. subscapularis. Before exposing 
the A. subscapularis first trace the branch, A. thoracico-dorsalis, that arises 
from the subscapularis i to 2 cm. from its origin (PI. I, immediately below 
22). This artery extends obliquely across the inner face of the teres major 
supplies small branches to it and to the axillary lymph gland and terminates 
in the latissimus and panniculus. Transect the M. teres major near the 
middle and turn it aside. Now trace the A. subscapularis between the 
Mm. subscapularis and teres major across the inner surface of the caput 
longtim tricepitis to the posterior angle of the scapula. The A. subscap- 
ularis gives ofif the following branches: » 

(i) A. thoracico-dorsalis already dissected. See above. 

(2) A. circumflexa humeri posterior arises i to 2 cm. peripheral to 
the A. thoracico-dorsalis. It accompanies the N. axillaris to the deep face 
of the M. deltoideus and is distributed to this muscle and also to the caput 
longum, the caput laterale, the brachialis, the teres minor and a small twig 
to the capsule of the scapulo-humeral joint. 

(3) A. circumflexa scapulae arises from the subscapularis 5 to 8 cm. 
peripheral to the A. circumflexa humeri posterior and extends directly to 
the posterior border of the scapula; here it divides into two branches of 
which one passes to the outer and the other to the inner surface of the 
scapula. The outer branch crosses, at nearly a right angle, the outer face 
of the scapula, a little below the spine, and is distributed to the infra and 
supraspinati and the teres minor. The inner branch is distributed to the 
subscapularis. The general course of these vessels is indicated by the 
vasciilar grooves of the scapula. (See cleaned scapula.) 

(4) Rami musculares. Numerous small branches of the A. sub- 
scapularis are supplied to the IVIm. subscapularis and teres major. Two 
or more large branches of the A. subscapularis are given off to the caput 
longum, the tensor fasciae antebrachii, the infraspinatus and the deltoideus. 
The V. subscapularis accompanies the artery. 

A. circumflexa humeri anterior arises from the brachialis i to 4 cm. periph- 
eral to the subscapularis. It passes between the hixmerus and the M. 
coraco-brachialis, supplies a branch to this muscle and terminates in the 
biceps brachii and mastoido-hiuneralis. (The biceps may now be tran- 
sected.) It gives off a branch which extends towards the scapiilo-humeral 
joint and is distributed to the biceps brachii and its s^^novial tendon sheath. 
Occasionally the A. circumflexa humeri anterior is a small vessel supplying 
only the coraco-brachialis. 



14 

A. profunda brachii (PI. I, 24) is a large but very short trunk, i to 3 cm. 
in length, which arises from the brachialis near the middle of the brachium, 
or at the level of the lower border of the tendon of the teres major and latis- 
simus. The artery divides into several branches which are distributed 
to the caput longtmi, caput laterale and the brachialis. Not infrequently 
this artery is double at its origin. 

A muscular branch to the biceps brachii originates from the anterior side 
of the brachialis, 6 to 8 cm. distal to the A. profunda brachii and nearly 
opposite the A. ulnaris, and enters the biceps a little below the middle 
of the muscle (PI. I). Occasionally it gives off a branch of considerable 
size to the M. brachialis. Turn aside the distal portion of the tensor fasciae 
antebrachii taking care not to ctit the cutaneous nerve (a branch of the 
ulnaris) which lies at the anterior border of this portion of the muscle. 

A. ulnaris (PI. I, 25) arises from the brachialis near the nutrient foramen, 
at the distal third of the shaft of the humerus. The artery passes beneath 
the tensor fasciae antebrachii and along the anterior border of the caput 
mediale to the posterior part of the humero-radial joint where it passes 
beneath the antebrachial aponeurosis and the small ulnar head of the 
M. flexor carpi medius. Its further course along the antebrachium should 
be deferred until later. 

Branches of A. ulnaris. Close to its origin it gives off a long small 
branch that winds obliquely across the internal and anterior faces of the 
tendon of the biceps brachii and extends to the posterior superficial pectoral 
and to the antebrachial aponeurosis. (Sometimes this small branch arises 
from the A. brachialis) (PI. I, just below 34')- About i to 2 cm. peri- 
pheral to the above branch the A. ulnaris gives off a larger, long, branch 
to the middle and posterior portions of the posterior superficial pectoral. 
The A. ulnerus also gives off one or more small branches to the tensor 
fasciae antebrachii and a branch of considerable size enters the olecranon 
fossa and supplies the joint capsule. The V. ulnaris accompanies the 
artery. 

A. nutritia humerii (nutrient artery of the hiunerus). 

The nutrient artery of the humerus sometimes arises directly from the 
brachialis and sometimes from the ulnaris. It passes directly into the 
nutrient foramen of the humerus. 

Remove the skin from the inner side of the antebrachium, if it has not 
already been removed, and slit longitudinally the antebrachial aponeurosis. 
Identify the small, thin, ulnar head of the flexor carpi medius (PI. I, 17'); 



15 

turn this aside taking care not to cut the very smah filament supphcd to it 
from the N. ulnaris which Has immediately under the ulnar head of this 
muscle (PL I, e). Now trace the A. ulnaris (vein and nerve also) along 
the antebrachium noting that in the proximal half of this region the artery 
lies between the ulnar and humeral heads of the flexor perforans and in 
the distal half of the antebrachium it lies between the flexor carpi medius 
and the flexor carpi extemus. Note that the nerve, artery and vein lie 
side by side and are immediately beneath the aponeurosis. Transect the 
flexor carpi medius near its middle and reflect the distal portion in order 
to expose the supracarpal arch which is formed by the anastomosis of 
the A. ulnaris with a branch from the A. metacarpae volaris lateralis, a 
little proximal to the carpus (PL III, i6). In demonstrating this vascular 
arch be careful not to cut any of the vessels arising from it. Two to four 
centimeters below the origin of the A. ulnaris the A. brachialis divides into 
its' two terminal branches — the A. radialis anterior and the A. radialis 
posterior. 

N. ulnaris (PL I, 39) arises from the ist and 2d thoracic nerves. It lies 
posterior to the brachial artery and vein and between the median and 
radial nerves, the median being anterior and the radial posterior to it. 
Near the middle of the brachium the nerve passes beneath the tensor 
fasciae antebrachii and extends to the humero-radial joint where, with the 
A. and V. ulnaris, it dips beneath the small ulnar head of the flexor carpi 
medius (PL I, 17')- Near the middle of the brachium, a little before pass- 
ing beneath the tensor fasciae antebrachii, the nerve gives off a cutaneous 
branch which extends along the anterior border of the tensor fasciae ante- 
brachii and between it and the posterior superficial pectoral (PL I, a). 
The nerve does not supply the posterior superficial pectoral but passes 
through it and extends subcutaneously along the posterior face of the ante- 
brachium nearly to the carpus. At the humero-radial joint the N. ulnaris 
gives off several branches the smallest of which supplies the ulnar head of 
the flexor carpi medius (PL I, e); a larger branch goes to the ulnar head 
of the flexor perforans (PL I, d) and the two largest branches are distributed 
one to the humeral head of the flexor carpi medius, and the other to the flexor 
perforatus. Occasionally the humeral head of the flexor perforans receives a 
branch from the N .ulnaris. These branches are all easily demonstrated and need 
no special directions for their dissection other than to turn aside the proximal 
portion of the flexor carpi medius in order to see the place where the branch 
that supplies it enters its deep face near the proximal end of the muscle. 
Now trace the N. ulnaris along its antebrachial course, noting carefully 
its relation to the aponeurosis, to the flexor perforans to the middle and 



i6 

external flexors of the carpus and to the artery and vein. Five to eight 
centimeters from the carpus the nerve divides into two branches of which 
one pierces the aponeurosis and passes, subcutaneously, across the tendon 
of the flexor carpi externus and divides into numerous branches which extend 
obliquely to the antero-lateral face of the carpus and metacarpus (PI. Ill, 
25'; PI. II, 26). The other terminal branch of the N, ulnaris unites with a 
branch of the N. medianus, below the supracarpal arch, and thus forms the 
N. volaris lateralis (PI. Ill, 26). 

A. radialis anterior (PI. II, 19) is the smaller of the two terminal branches 
of the A. brachialis. It passes obliquely downward and outward between 
the anterior face of the humerus and the Mm. biceps brachii and the 
brachialis. Transect the brachialis where it crosses the external surface of 
the tendon of the biceps. Beneath the brachialis and the extensor carpi 
radialis, the artery supplies branches to these muscles. Beneath the exten- 
sor digitalis communis the A. radialis anterior gives off two or three small 
branches to this muscle; it also sends a branch to the extensor digitalis 
lateralis and to the flexor carpi externus. The A. radialis anterior is 
continued as a small branch which extends along the antero-intemal 
aspect of the radius to the carpus where it joins the rete carpi dorsalis. 

A. radialis posterior (PL I, 26) is the direct continuation of the A. brachialis 

and is the larger of its two terminal branches. The artery crosses the 
antero-intemal face of the humero-radial joint and is here covered by 
the skin, the aponeurosis and the posterior superficial pectoral muscle. 
Note that in this region the N. medianus, as it passes from the posterior 
to the anterior side of the artery and vein, lies superficially to the blood- 
vessels (PL I). A little below the humero-radial joint the A. radialis 
posterior, accompanied by the N. medianus, passes under the flexor carpi 
internus (PL I, 16) which should be transected and turned aside. Beneath 
this muscle it extends to the distal third of the shaft of the radius and is then 
continued by the large A. digitalis communis and the two metacarpal 
arteries. 

Branches of the A. radialis posterior. 

(i) One or more small branches to the humero-radial joint. 

(2) Muscular branches to the flexor carpi internus and medius and 
to the flexor perfortus and perforans. 

(3) A. interossea communis, is a large branch that arises from the 
radialis posterior near the level of the radio-ulnar arch through which the 
interossea communis passes. In the interosseous space it gives off the 
nutrient artery of the radius. After passing through the interosseus space 



17 

the artery gives ofif one or more branches to the flexor carpi extemus, 
anastemoses with the radiahs anterior, and is continued along the antero- 
extemal face of the radius, beneath the common digital extensor, to the 
carpus where it anastemoses by a fine branch with the radialis anterior 
and also commonly joins the rete carpi dorsalis. Near the proximal third 
of the radius it gives off a small branch which runs along the extensor digi- 
talis lateralis, supplies twigs to this muscle and to the extensor carpi obliquus. 
One or two centimeters distal to the interossea communis the A. radialis 
posterior may give off another branch nearly as large as the A. interossea 
communis. This second branch (in the present specimen) crosses at a 
right angle the posterior face of the radius then turns towards the carpus 
and is distributed by numerous branches to the flexor perforans and flexor 
perforatus. 

N. medianus (PI. I, 32) arises from the 8th cervical and ist thoracic nerves. 
Immediately below the A. axillaris the nerve usually receives a large branch 
from the N. musculo-cutaneous thus forming with it a loop through which 
the artery passes (PL I) . Near the middle of the brachium the N. medianus 
gives off a large branch which extends very obliquely beneath the biceps, 
rarely sending a small filament to it, and divides into two branches (PL I, 
34, 35) of which one is distributed to the brachialis; the other branch 
winds very obliquely across the lateral face of the biceps, near the distal 
end, to the antero-internal face of the antebrachium where it divides into 
two principal branches which accompany the two respective subcutaneous 
veins, i.e. the cephalic and accessory veins, on the inner surface of the 
antebrachium (PL I, 34') • The vein should of course, be dissected along with 
the nerves. The larger of the two subcutaneous branches of the nerve may 
be traced to the middle of the metacarpus. The main trunk of the N. 
medianus and the artery and vein radialis posterior, after crossing the 
humero-radial joint, pass beneath the flexor carpi internus as already 
demonstrated (PL I, 16). Note very carefully the relation of the nerve, 
artery and vein to each other and to the posterior superficial pectoral 
muscle and to the internal tuberosity of the radius. Median neurectomy 
is performed in this region and also the pulse may here be readily felt. 
A little before the N. medianus passes beneath the flexor carpi internus it 
gives off two or three branches which are distributed as follows: One or 
two branches, to the flexor carpi internus (PL I, 36); a much larger branch 
which soon divides into two parts both of which are distributed to the 
humeral portion of the flexor perforans (PL I, 37) ; and finally a small nerve 
which also divides into two branches (PL I, 38) one of which extends into 
the radio-ulnar arch and is distributed principally to the periosteum; the 



other branch extends along the posterior face of the radius to the radial 
head of the flexor perforans to Which it is distributed. Continue the dis- 
section of the N. medianus in its course beneath the flexor carpi internus. 
Near the distal third of the antebrachium the nerve (PL III, 24) divides 
into two terminal branches one of which unites with a branch of the N. 
ulnaris as already seen, and with it forms the N. volaris lateralis (PI. Ill, 
26); the other terminal branch of the N. medianus forms the N. volaris 
medialis (PI. Ill, 27). 

N. volaris lateralis, as already stated, is formed by the union of two branches, 
one from the N. ulnaris and the other from the N. medianus. The N. 
volaris lateralis, accompanied by a small artery (A. metacarpea volaris 
lateralis) and vein, crosses the carpus at the medial side of the pisiform 
bone, in a special channel in the carpal sheath. At the proximal end of 
the metacarpus the nerve gives off a large branch to the suspensory ligament ; 
before tracing this branch however, follow the N. volaris lateralis as far 
as to the fetlock noting the branch of considerable size from the N. volaris 
medialis that joins it a little proximal to the distal end of the rudimentary 
metacarpal (PL III, 28). Transect the two flexor tendons near the middle 
of the metacarpus taking care not to injure the N. volaris medialis and the 
large artery and vein at the medial side of the tendons (PL III). Reflect 
the proximal portion of the tendons and carefully trace the branch from 
the N. volaris lateralis to the suspensory ligament to which it supplies 
more small branches and also two branches that accompany the respective 
two or arteries metacarpea volaris medialis and lateralis. 

A. retis carpi volaris is a small vessel which arises from the A. radialis 
posterior near the distal third of the antebrachiiim and descends to the 
posterior surface of the carpus where it divides into several small branches 
which help to form the rate carpi volare. 

A. metacarpea volaris lateralis. This is the smallest of the three branches 
that continue the A. radialis posterior. It arises from the lateral side of 
the A. radialis posterior, crosses the medial face of the pisiform bone, with 
the N. volaris lateralis, and continues to the proximal end of the meta- 
carpus. Here it is connected with the A. metacarpea volaris medialis 
usually by two transverse branches, thus forming the arcus volaris pro- 
fundus. The larger of the two transverse branches lies between the sub- 
carpal or inferior check ligament of the perforans tendon and the suspensory 
ligament: the other transverse branch, not always present, lies between 
the suspensory ligament and the large metacarpal bone. Cut the suspen- 
sory ligament near the middle and draw it aside. Below the deep vascular 



19 

arch, the A. metacarpa volaris lateralis runs in a flexuous course on the 
posterior face of the large metacarpal bone, close to the lateral rudi- 
mentary metacarjDal. Near the distal third of the metacarpus the artery- 
unites with the A. metacarpea volaris medialis to form a short trunk which 
joins the A. digitalis lateralis close to the origin of the latter. 

A. metacarpea volaris medialis (PI. Ill, 17) arises from the radialis posterior, 

usually a little proximal to the metacarpea volaris lateralis, and is con- 
siderably larger than that artery. It passes across the postero-internal 
face of the carpus with the large vein of the same name, imbedded in the 
carpal sheath or posterior annular ligament. At the proximal end of the 
internal rudimentary metacarpal it is connected with the A. metacarpea 
volaris lateralis, usually, by two transverse branches (arcus volaris pro- 
fundus) as mentioned above. It then continues in a flexuous course, on 
the posterior internal face of the large metacarpal, to near the distal third 
of the metacarpus where it unites with the metacarpea volaris lateralis 
to form a short common trunk which joins the A. digitalis lateralis. The 
nutrient artery of the large metacarpal bone is a branch of the metacarpea 
volaris medialis. 

A. metacarpea dorsalis lateralis and A. metacarpea dorsalis medialis are 

two very small arteries that have a variable origin. Sometimes they arise 
from the A. metacarpea volaris, of the same side, at the level of the deep 
vascular arch. They extend anteriorly across the heads of the rudimentary 
metacarpals, descend in the grooves between the large and small metacarpal 
bones, and anastamose with the corresponding A. metacarpea volaris. 
Sometimes these two small arteries arise from the rete carpi dorsalis and 
in other cases, they arise in part from the rete carpi dorsalis and in part 
from the A. metacarpea volaris lateralis and the A. metacarpea volaris 
medialis. 

A. digitalis communis (PL III, 18) is the largest and most direct, continua- 
tion of the A. radialis posterior. It extends through the carpal canal at 
the medial side of the flexor tendons, in company with the N. volaris 
medialis. Slit open the carpal canal and trace the artery and the large 
metacarpal vein that, in the metacarpal region, accompanies the artery 
along the medial side of the flexor tendons to near the fetlock where the 
artery divides into the A. digitalis lateralis and the A. digitalis medialis. 
Remove the hoof or horn capsule. 

N. volaris medialis (PL III, 27) is formed by one of the terminal branches of 
the N. medianus. It passes through the carpal canal in close company with 



20 

the large A. digitalis communis and both artery and nerve are in close 
relation with the flexor tendons. Note that near the middle of the meta- 
carpus the nerve gives off a large branch which crosses very obliquely the 
posterior face of the flexor tendons and joins the N. volaris lateralis a little 
above the distal extremity of the nidimentary metacarpal (PI. Ill, 28). 
At the level of the sesamoid bones of the fetlock, the nerve divides into 
two, sometimes three, branches, viz., an anterior, a middle, if present, and a 
posterior branch (PI. Ill, 30, 31, t,2). These branches are of very unequal 
size, the posterior being much the largest and the most important. This 
branch is the one that is cut in the operation of low neurectomy. The anter- 
ior branch descends in front of the vein and is distributed to the skin on the 
anterior face of the digit and to the coronary band or matrix. The middle 
branch is small and irregular; it descends between the artery and vein and 
is generally formed by the union of several small branches which cross over 
the artery before uniting. This branch terminates in the coronary band 
or matrix and the sensitive laminae. The posterior branch lies close behind 
the artery, except at the fetlock, where the nerve is more superficial than the 
artery. This posterior branch accompanies the digital artery and will be 
traced with it. It is distributed to the sensitive laminae, sole and frog. 

A. digitalis lateralis and A. digitalis medialis are formed by the bifur- 
cation of the digitalis communis near the distal third of the metacarpus. 
Each artery passes over the outer surface of the corresponding sesamoid 
bone at the fetlock, and descends parallel to the borders of the deep flexor 
tendon to the volar foramina of the third phalanx; in the semilunar canal 
of this bone the two arteries anastomose with each other. Expose the 
artery of one side, as follows: remove the lateral cartilage and the anterior 
or apical two-thirds of the plantar cushion; remove also, the portion of 
the deep flexor tendon that is exposed by the removal of the anterior part 
of the plantar cushion, i.e. the portion of tendon in relation to the navicular 
bone and the semilunar crest of the third phalanx. Each digital artery is 
accompanied by a vein and the two or three branches of the volar nerves. 
Proximal to the fetlock the artery lies deeply and is covered by the vein 
and nerve; at the fetlock the three structures lie at the same level, the vein 
being anterior and the large posterior branch of the nerve back of the artery. 
The anterior branch of the volar nerve crosses obliquely the digital 
artery and vein at, or a little below, the fetlock (PI. Ill, 30). The vessels 
and nerves are crossed obliquely by a small ligamentous band extending 
from the ergot to the fascia at the side of the first interphalangal or pastern 
joint (PI. Ill, 13). 



21 

Branches of the A. digitalis lateralis. 

(i) Numerous small branches to the ergot, joints, tendons and tendon 
sheaths. 

(2) A. phalangis primae. (Artery of the first phalanx). This is a 
short trunk whicli arises at a right angle near the middle of the first phalanx 
and divides almost immediately into an anterior and a smaller posterior 
branch. The anterior branch divides into an ascending and a descending 
portion both of which are distributed on the anterior face of the first phalanx. 
A branch passes between the extensor tendon, which should be cut, and the 
first phalanx and anastamoses with the corresponding artery of the oppo- 
site side. The small posterior branch of the A. phalangis primae divides 
into several branches of which one passes between the infrasesamoidean 
ligaments and the first phalanx and anastomoses with the opposite artery; 
the other branches are distributed to the structures on the posterior face 
of the first phalanx. 

(3) A. toricae phalangis tertia (artery of the plantar cushion) arises 
at a right angle from the digitalis, at the proximal border of the lateral 
cartilage. It extends postero-distally and is distributed to the plantar 
cushion and to the matrix of the frog. 

(4) A. dorsalis phalangis secundae (dorsal or anterior artery of the 
second phalanx). This artery arises at a right angle from the digitalis, 
near the middle of the second phalanx, and under cover of the lateral 
cartilage. It extends anteriorily beneath the lateral cartilage and the 
extensor tendon and anastomes with its fellow of the opposite side. Just 
as it passes beneath the extensor tendon it gives off a branch to the coronary 
band or matrix ; it also supplies small branches to the tendon and to the 
joint capsule. A branch of the volar nerve accompanies the artery. 

(5) A. volaris phalangis secundae (ventral or posterior artery of the 
second phalanx) is smaller than the preceding opposite to which it arises. 
It passes above the proximal border of the navicular bone and anastomoses 
with its fellow of the opposite side. 

(6) A. dorsalis phalangis tertiae (dorsal artery of the third phalanx) arises 
from the digitalis at the inner or medial side of the wing of the third phalanx. 
In company with the posterior branch of the N. volaris, it passes through 
the notch (or foramen) of the wing of this bone and extends anteriorly in 
the vascular groove on the lateral surface of the bone. It gives off a pos- 
terior branch to the plantar cushion. 

The branches of the A. digitalis medialis are the same as those of the 
A. digitalis laterales. 



PLATE I 
MEDIAL OR INNER VIEW OF THE PECTORAL LIMB 

1. i' Posterior superficial pectoral. 

2. Anterior superficial pectoral. 

3. Posterior deep pectoral. 

4. Anterior deep pectoral. 

5. M. supraspinatus. 

6. M. subscapularis. 

7. M. teres major. 

8. M. latissimus dorsi. 

9. M. panniculus. 

g'. Aponeurotic tendon of panniculus. 

10. to'. Tensor fasciae antebrachii. 

11. M. caput longum tricipitis. 

12. M. caput mediale tricipitis. 

13. M. coraco-brachialis. 

14. M. biceps brachii. 

15. Aponeurotic tendon-slip from biceps brachii. 

16. M. flexor carpi internus. 

17. M. flexor carpi medius. 

17'. Ulnar head of flexor carpi medius. 

18. Ulnar head of flexor perforans. 

19. M. flexor perforatus. 

20. M. flexor perforans. 

21. A. axillaris. 

22. A. subscapularis. 

23. A. brachiaHs. 

24. A. profunda brachii. 

25. 25'. A. ulnaris. 

26. A. radialis posterior. 

VII, VIII, I, II, = 7th - 8th cervical and 1st and 2d thoracic nerves. 

27. Nerve to anterior deep pectoral. 

28. N. suprascapularis. 

29. 29'. N. musculo-cutaneous. 

30. 30'. Nn. to anterior and posterior superficial pectorals. 

31. Nn. to posterior deep pectoral. 

32. 32'. N. medianus. 

33. Ner\-e filament to biceps brachii (very rarely present). 

34. 34'. Cutaneous branch of N. medianus. 

35. Branch of N. medianus to M. humeralis obliquus. 

36. Branch to M. flexor carpi internus. 

37. Branch to flexor perforans. 

38. Small branch to radial head of flexor perforans and to the radio-ulnar arch. 

39. 39'- N. ulnaris (a) cutaneous branch; (b) branch to M. flexor carpi medius; (c) branch to flexor 

perforatus; (d) branch to ulnar head of flexor perforans; (e) branch to ulnar head of flexor per- 
/< foratus. 

40. "^; radialis. 

41 
42, 

43 



44 
45 
46 

47 
48 

49 



Branch to caput longum tricipitis. 

Branch to caput longum, laterale, mediale and anconeus. 

Portion of N. radialis that continues along the spiral groove to the extensors of the metacarpus and 

phlanges. 

Branch of N. radialis to the M. tensor fasciae antebrachii. 
Nerve to the panniculus and posterior deep pectoral. 
N. axillaris. 
Nn. subscapulares. 
Nerve to the M. latissimus dorsi. 
Axillary lymph gland. 



49' Lymph gland. 



PLATE II 

LATERAL OR EXTERNAL VIEW OF THE PECTORAL LIMB 

1. M. supraspinatus. 

2, 3, 3'- M. deltoideus (transected and turned aside). 

4. M. teres minor. 

5. M. caput longum tricipitis. 
5'. M. tensor fasciae antebrachii. 

6. 6'. M. caput laterale tricipitis (transected and tlie distal portion turned back). 

7. M. anconeus. 

8. M. biceps brachii. 

9. M. mastoido-hunieralis. 

10. M. brachialias. 

11. 11'. M. extensor carpi radialis (transected and the distal portion turned aside). 

12. Radius. 

13. 13'. M. extensor digitalis communis (extensor pedis) a portion of the muscle has been removed. 

14. M. extensor carpi obliquus. 

15. Ulnar head of M. flexor perforans. 

16. M. flexor carpi externus. 

17. M. extensor digitalis lateralis. 

18. M. flexor perforans. 
ig, 20. A. radialis anterior. 

21. N. suprascapularis. 

22. N. axillaris. 

23. Cutaneous branch of N. axillaris. 

24. Branch of N. axillaris to M. mastoido-humeralis. 

25. 25'. N. radialis. 

a. a'. Branch of N. radialis to caput laterale tricipitis. 

b. Branch to M. anconeus. 

c. Cutaneous branch of N. radialis. 

d. Branches of N. radialis to M. extensor carpi radialis. 

e. Branches to M. extensor digitalis communis. 

f. Branch to M. extensor carpi obliquus. 

g. Branch to M. extensor digitalis lateralis. 

h. Termination of N. radialis in the M. flexor carpi externus. 

26. Cutaneous branches of N. ulnaris. 



PLATE III 
MEDIAL OR INNER VIEW 

1 . Radius. 

2. 2'. Principal and medial metacarpal bones. 

3. Lateral cartilage. 

4. M. extensor carpi radialis. 

5. M. extensor carpi obliquus. 

6. M. flexor carpi intemus. 

7. M. flexor perforatus. 

8. M. flexor carpi medius (turned aside). 

9. M. interosseus medius. 

10. M. lumbricalis medius. 

1 1 . Portion of carpal sheath or annular ligament. 

12. Suspensory or suprasesamoid ligament. 

13. Ligament of ergot. 

14. Cut edge of antebrachial aponeurosis (not clearly shown in figure). 

15. A. radialis posterior. 

16. Supracarpal arch. 

17. A. metacarpea volaris medialis. 

18. A. digitalis communis. 

19. A. digitalis medialis. 

20. A. ulnaris. 

21. 22. V. radialis posterior. 

23. V. ulnaris. 

24. N. medianus. 

24'. Branch of N. medianus to the N. ulnaris. 

25. N. ulnaris. 

25'. Cutaneous branch of N. ulnaris. 

26. N. volaris lateralis. 

27. N. volaris medialis. 

28. Anastomosing branch from N. volaris medialis to the N. volaris lateralis. 

29. Small branch to region of ergot. 

30. 31, 32. Anterior, middle and posterior branches of the N. volaris medialis. 
33. Coronary band of matrix. 



Dissection of the Blood -Vessels and Nerves of 
the Leg or Pelvic Limb 

Remove the intestines and transect the body immediately caudal to 
the last pair of ribs. In the male, find the spermatic veins and the much 
smaller spermatic arteries near the peritoneal or vaginal ring through 
which they, together with the ductus deferens or spermatic duct, pass to 
the testes. Trace the right spermatic vein to the posterior vena cava, 
and the left one to the left renal vein (or to the posterior vena cava, close 
to the renal vein) ; also trace the spermatic arteries to their respective 
places of origin — the right spermatic artery, from the A. mesenterica 
posterior and the left one from the aorta a little cephalad of the preced- 
ing; sometimes both of these arteries arise from the aorta close to the A. 
mesenterica posterior. In the female the utero-ovarian arteries correspond 
to the spermatic arteries but are much shorter. Each artery passes in a 
tortuous manner between the two peritoneal layers of the anterior part 
of the broad ligament of the uterus and divides into two branches of 
which one is distributed to the ovary and the other to the cornu of the 
uterus. Clean up the aorta (and vena cava) taking care not to remove the 
lumbar lymph glands which lie near the place where the aorta divides into 
the Aa. iliaca externa and interna, (sometimes spoken of as the terminal 
branches of the aorta) (PL V, 30, 34). Note the size, number and location 
of the lumbar lymph glands. The posterior portion of the body should 
now be divided into halves by a sagittal section through the Ivimbar and 
sacral vertebrae, the pelvic symphysis and the pelvic organs. Identify 
each lumbar and sacra vertebra. Identify also the trunk of the sympa- 
thetic nerve which, in this region, lies on the ventro-lateral face of the 
bodies of the vertebrae and is covered by the aorta and the posterior vena 
cava (PI. V, 45). This nerve trunk and its connections with each of the 
lumbar and sacral nerves, by the rami communicantes, should be noted 
as the dissection of the lumbo-sacral nerve plexus proceeds. 

A. circumfiexa iliaca (PI. V, 29) usually arises from the A. iliaca externa, 

close to its origin, but sometimes directly from the aorta. It extends 
laterally across the ventral surface of the psoas muscles and divides into 
an anterior and a posterior branch shortly before it reaches the pos- 
terior border of the M. transversus abdominis. Transect the transversus 
abdominis near the middle of its fleshy portion and turn it aside. Note 
the location and size of the external iliac lymph glands (PI. V, 64) which 



28 

are situated near the bifurcation of the A. circumflexa iliaca. Dissect up 
the peritoneum cephalad of the peritoneal or vaginal ring and note very 
carefully the relation of this ring and the spermatic cord, to the posterior 
edge of the M. obliquus internus. Do not confuse the M. cremasteric 
externa with the obliquus internus. Transect the obliquus internus a little 
dorsal to the peritoneal ring. Now trace the anterior branch of the A. 
circumflexa iliaca. At, or near, its origin it may give off one or two small 
branches to the psoas magnus and iliacus. About 5 cm. from its origin 
this anterior branch divides into two branches which are distributed to 
the Mm. transversus, abdominis obliquus internus and obliquus externus. 
The posterior branch of the A. circumflexa iliaca, 5 to 8 cm. from its origin, 
also divides into two branches of which one goes to the obliquus internus 
and the other, after perforating the abdominal wall near the external angle 
of the ilium, runs downward on the inner face of the M. tensor fasciae latae, 
about 5 cm. from its anterior border, and is distributed to the panniculus, 
the precrural or subiliac lymph gland and to the inner face of the tensor 
fasciae latae. To demonstrate this latter branch reflect the skin in the 
region of the flank and dissect between the abdominal wall and the inner 
face of the tensor fasciae latae. Find the artery (and vein) on the inner 
surface of the tensor fasciae latae, 5 to 8 cm. from its anterior border, and 
trace it in both directions. 

Internal inguinal ring. 

The internal inguinal ring should not be confused with the small peri- 
toneal or vaginal ring of the male. The internal inguinal ring is from 10 
to 12 cm. in length, measured from the prepubic tendon to the dorsal margin 
of the peritoneal ring. The anterior boundaiy of the internal inguinal 
ring is formed by the posterior edge of the M. obhquus internus; the pos- 
terior boundary is formed by the inguinal ligament. In the male the follow- 
ing structures pass through the inguinal canal, viz., the evaginated peritoneum 
of the spermatic cord, the ductus deferens or spermatic duct, the spermatic 
nerves, artery and vein and lymph vessels, the A. pudenda externa and 
the M. cremasteric externa. The skin in the region of the external inguinal 
ring should now be carefully turned aside in order to expose the superficial 
inguinal lymph gland, the external inguinal ring and the structures which 
pass through it. The superficial inguinal lymph gland forms a large mass, 
8 to 10 cm. long, which lies anterior to the external inguinal ring. In the male 
the gland extends along the course of the A. abdominalis subcutanea on 
either side of the penis ; in the 'female the gland is situated between the 
mammary gland and the abdominal wall. Now turn aside the portion of 
the M. obliquus internus that forms the anterior boundary of the internal 



29 

inguinal ring and note that the space (i.e. the inguinal canal) occupied by 
the spermatic cord is bounded posteriorly by the inguinal ligament and 
anteriorly, by the M. obliquus internus; note also that the length of the 
canal from the external inguinal ring to the level of the peritoneal ring, 
measured along the spermatic cord, is about lo cm. 

A. iliaca externa (PI- V, 30) arises from the aorta at the level of the ^pn 
lumbar vertebra and extends obliquely ventrally, at the side of the pelvic 
inlet, to the level of the anterior edge of the pubis where it is continued 
as the A. femoralis. Remove the overlying peritoneum and fascia. Note 
that the large V. iliaca externa is immediately posterior to the artery. The 
termination of the A. iliaca externa and the beginning of the A. femoralis 
is indicated by the truncus pudendo-epigastricus or prepubic artery. 

Truncus pudendo-epigastricus or prepubic artery (Pl.V, 31) is only6to8cm. 
in length. It arises from the A. iliaca externa near the level of the anterior 
border of the pubis. The artery crosses the dorsal or free edge of the 
inguinal ligament and extends for a short distance along the abdominal or 
anterior face of the ligament to the internal inguinal ring where it divides 
into two branches — A. epigastrica caudalis or posterior abdominal and A. 
pudenda externa or external pudic. 

(i) A. epigastrica caudalis (or posterior abdominal). 

This branch of the pudendo-epigastric trunk extends cephalad along 
the lateral border of the M. rectus abdominis to which it is principally dis- 
tributed; small twigs however, are also supplied to the transversus ab- 
dominis and the obliquus internus. The artery is accompanied by a vein. 

(2) A. pudenda externa (or external pudic). 

This artery and its branches may be readily exposed by dissecting, 
en masse, the sheath and penis from the abdominal wall as far back as to 
the external inguinal ring taking care not to cut the artery as it emerges 
from the ring at the postero-internal commissure. 

The A. pudenda externa is from 4 to 6 cm. in length. Immediately after 
it passes through the external inguinal ring it divides into two branches— 
the A. abdominalis subcutanea and the A. dorsalis penis. Trace the former 
cephalad, along the side of the sheath, to which and to the superficial inguinal 
lymph gland it is distributed. The dorsal artery of the penis passes to the 
dorsum of that organ and terminates at the glans penis. It gives off col- 
lateral branches to the corpus cavernosum one of which usually passes 
posteriorly and anastomoses with a branch of the A. obturatoria. In the 
female the mammary artery takes the place of the dorsal artery of the penis. 
Note that the enormous venous plexus on the dorsal and lateral sides of the 



30 

penis, (or the mammary glands) is drained mainly by the large V. pudenda 
externa (PL V, 42), which lies in the subpubic groove of the pelvis. 

A. pudenda interna (PI. V, 37). 

Care must be exercised in tracing this artery especially its distal half, not 
to injure its numerous small branches or the neighboring nerves; the adjoin- 
ing veins however, may be cut if desired. The urocyst and all of the other 
pelvic organs should be turned dorsally. The A. pudenda interna arises 
from the A. iliaca interna near the origin of the latter vessel. It extends 
posteriorly across the lateral wall of the pelvic cavity, lying close to the 
dorsal border of the iliac portion of the M. obturator internus. Opposite 
the superior ischiatic spine the artery is covered by the M. retractor ani 
which should be transected and turned aside (PI. V, 21 and 21'). Near the 
lesser sacro-sciatic foramen the artery either passes through the sacro- 
sciatic ligament i.e. from its inner to its outer surface, or is imbedded in the 
substance of the ligament. Trace the artery peripherally as far as can 
be done readily (to the posterior border of M. retractor ani) and then 
proceed as follows: make a circiilar cut in the skin of the anal region at a 
little distance, 4 to 6 cm., from the anal orific; also cut the large bundle of 
muscle fibres (recto coccygeal, PL V 23) that attaches the terminal part of 
the rectvun to the coccygeal vertebrae. Cut also, the M. retractor penis 
(PL V, 22). Now carefully remove the connective tissue from the side of 
the anus vintil the artery and nerves are exposed. The main trunk of the 
artery terminates in the erctile tissvie at the root of the penis. 

Branches of the A. pudenda interna. 

(i) A. umbilicalis (PL V, 39) arises from the pudenda interna 2 to 3 cm. 
from the origin of that vessel and passes directly to the urocyst. Before 
birth the A. umbilicalis is a very large vessel and carries the foetal blood 
to the placenta. After birth the vessel extends only to the urocyst and is 
very mvich smaller than in foetal life. 

(2) A. haemorrhoidalis media (or vesico-prostatic) . This small artery 
in the male, arises from the pudenda interna about 8 cm. from the origin 
of the latter (or about half way between the origin of the A. pudenda 
interna and the anterior edge of the M. retractor ani) and runs posteriorly. 
It supplies small twigs to the rectum, urocyst, prostate gland, and seminal 
vesicle. Near the ischial arch the A. pudenda interna gives off a small 
branch — A. perinei — which passes somewhat dorsally at the side of the 
anus which it supplies; the A. pudenda interna also gives off twigs to the M. 
bulbo-cavemosus and the skin of the perineum. In the female the corres- 
ponding artery is much larger and gives off the A. uterina caudalis. This 



31 

runs cephalad on the side of the vagina to which it gives branches and 
ramifies on the body of the uterus, anastomosing with the anterior and 
middle uterine arteries. 

N. femoralis (PL V, 46, PI. VII, 14) originates from the ventral divisions of 
the 3d, 4th, 5th and 6th lumbar nerves; very commonly however, the branch 
from the 6th lumbar nerve is wanting. Turn aside or remove the iliac 
fascia from the ventral surface of the sublumbar mtiscles. The proximal 
portion of the N. femoraUs is covered by the M. psoas parvus. Transect 
this muscle a little caudal to the A. circumflexa iliaca and turn its distal 
portion toward the median plane. The large N. femoralis will now be 
seen to have the same general direction ventro-caudally, as the A. ihaca 
externa. Transect the psoas magnus at the same level as the psoas parvus; 
separate the two muscles from each other sufficiently to trace the N. femoral- 
is to its respective places of origin from the 3d, 4th, 5th, and 6th, if present, 
lumbar nerves (PL V, in, iv,. v). Near its origin the N. femoralis lies at 
about the same level as the A. iliaca externa. At the ventral border of the 
tendon of the psoas parvus where the nerve passes under the anterior end of 
the M. sartorius (PL V, 11), the nerve Hes just anterior to the artery but is 
separated from it by the tendon of the psoas parvus which lies between the 
artery and the nerve (PL V, 8')- 

Branches of the N. femoralis. 

The first branch of the N. femoralis is given oft" a little peripheral to 
the place of junction of the ventral divisions of the 3d, and 4th lumbar 
nerves. It is a small branch supplied to the psoas magnus. The next 
branch, much larger than the preceding, leaves the N. femoralis a little 
peripheral to the junction of the 4th and 5th lumbar nerves. This second 
branch extends laterally between the psoas magnus and the iliacus and 
divides into several branches which are distributed to the M. iliacus; one 
or more small filaments may go to the psoas magnus. The remaining 
portion of the N. femoralis may be exposed as follows: Cut the femoral 
aponeurosis near its attachment to the M. obliquus extemus and remove it. 
With the fingers, principally, dissect between the muscles of the thigh and the 
posterior face of the inguinal ligament, leaving the ligament intact. Identify 
the M. sartorius and note its relation, together with that of the iliacus and 
the psoas magnus, to the ingviinal ligament. Free the sartorius from its 
attachment to the iUac fascia. Dissect between the sartorius and the 
M. gracilis taking care not to injure the nerve and blood-vessels that 
emerge from between these two muscles near the middle of the thigh. 
Transect the sartorius near the middle of the thigh. Draw aside the 



32 

proximal portion of the muscle taking care not to cut the small nerve 
branches it receives from the N. saphenus internus (PI. V, 47, 48) (a branch 
of the N. femoraKs) which lies immediately beneath the proximal half of 
the sartorius; also do not disturb the deep inguinal lymph gland which 
lies in the interstice between the sartorius and the pectineus (PI. V, 63). 
As the N. femoralis crosses the tendon of the psoas magnus it gives off the 
large branch just mentioned, N. saphenus internus, which runs beneath 
the sartorius for about one-half the length of the muscle, supplies small 
branches to it, as just stated. It then emerges with the A. and V. saphena 
interna, from between the adjacent borders of the sartorius and gracilis, 
near the middle of the thigh, where it breaks up into several large sub- 
cutaneous branches which are distributed to the inner and anterior faces 
of the thigh and leg. The longest of these branches accompanies the 
A. and V. saphena interna to the flexor side of the tarsus. Frequently the 
N. saphenus internus is divided into two parallel branches. After giving 
off the N. saphenus internus the main trunk of the N. femoralis, together 
with a large artery and vein, passes between the rectus femoris and the 
vastus internus into the quadriceps femoris group of muscles. Dissect 
between the vastus internus and the rectus femoris; transect the rectus 
femoris 10 to 15 cm. from its attachment to the patella and reflect the 
ends. The vastus internus also may be partially transected, if desired. 
Now trace the N. femoralis to its termination in the rectus femoris, vastus 
internus, vastus externus, and vastus intermedivts. The small M. capsu- 
laris is not supplied l:>y this nerve but by one of the gluteal nerves as 
mentioned later. 

Exposure of the A. iliaca interna, the A. sacralis lateralis and the sacral 
nerves (PI. V, 34, 35, 52, 54, 55, 56, 57, 60). 

Turn the rectum and other pelvic organs ventrally and find the small 
nerves (PI. V, 58) 2 to 4 in number, which lie between the peritoneum and 
the sacro-sciatic ligament and extend from the 2d, 3d, and 4th or from the 
3d and 4th only, sacral nerves towards the lateral side of the pelvic organs 
where, in connection with branches of the sympathetic nerve, they form 
an intricate network of nerves known as the hypogastric or pelvic plexus 
(PL V, 51). (If put on the stretch these two or more small nerves will 
stand out as more or less tense bands.) Great care must be exercised in 
exposing the A. (and V.) sacralis lateralis and the sacral nerves, because 
of their intimate relation to each other and to the sacro-sciatic ligament. 
Cut the ligament along the ventral mid surface of the V. sacralis lateralis 
and carefully turn it from the vein. It will now be seen that the largest 
of the sacral nerves, N. ischiadicus, 5 to 8 cm. in width (PL V, 54), originates 
from the 5th and 6th lumbar and the ist and 2d sacral nerves. This large 



33 

nerve trunk lies on the outer or lateral surface of the sacro-sciatic ligament 
and is not very liable to be mutilated. Two smaller nerves however, the N. 
pudendus (PL V, 57) and the N. haemorrhoidalis (PL V, 60) which originate 
from the 2d, 3d, and 4th or from the 3d and 4th, only, sacral nerves lie on 
the inner or pelvic surface of the sacro-sciatic ligament or else are imbedded 
in its substance. Each of these two nerves is from one-half to one centi- 
meter in width but is so thin, and in color so closely resembles the liga- 
ment that it is liable to be overlooked and removed along with the 
ligament. 

A. iliaca interna (PL V, 34) is a very large vessel and arises from the aorta 
close to the intervertebral disc between the 5th and 6th lumbar vertebrae. 
It runs under the wing or transverse process of the sacrum, then turns 
ventrally and extends along the pelvic surface of the shaft of the ilium to 
near the psoas tubercle of the ilium, where the vessel divides into its two 
terminal branches — the A. circumfiexa femoris lateralis (iliaco-femoral 
artery) and the A. obturatoria. To demonstrate this, remove a portion 
of the overlying V. iliaca interna. 

Branches of the A. iliaca interna. 

(i) The last one of the six lumbar arteries arises from the dorsal side 
of the A. iliaca interna and passes into the spinal canal through the inter- 
vertebral foramen between the last lumbar vertebra and the sacrum. 

(2) A. pudenda interna (PL V, 37), already described. See p. 30. 

(3) A. sacralis lateralis (PL V, 35). Remove the overlying V. sacralis 
lateralis. The A. sacralis lateralis arises from the iliaca interna close to 
the lumbo-sacral articulation. It extends along the sacrum ventral to the 
sacral foramina and the nerves that emerge from them. At the third 
sacral vertebra the artery divides into two branches — A. coccygeus lateralis 
and the much larger A. glutea posterior. Trace the A. coccygeus lateralis 
some distance along the tail to which it is distributed. The dissection 
of the A. glutea posterior must be deferred until the gluteal nerves are 
dissected. See p. 38. 

(4) A. iliolumbalis arises at a right angle from the lateral side of the 
iliaca interna, crosses the ventral surface of the ilium beneath or dorsal to 
the Mm. psoas magnus and iliacus to which it gives small branches. Tran- 
sect the M. iliacus opposite the artery. Draw aside the iliacus and the 
psoas magnus and trace the artery to where it crosses the external border 
of the ilium a little behind the external angle. Its terminal branches which 
will be demonstrated later, enter the gluteus niedius and the tensor fasciae 
latae. 



/> 



34 

(5) A. glutea anterior is the largest branch of the iliaca interna. It 
arises nearly opposite the iliolumbalis, passes through the greater sacro- 
sciatic foramen and immediately enters the gluteal muscles by several 
branches. These branches cannot be demonstrated until the gluteal 
muscles have been dissected. Frequently one of the radicals of the N. 
obturatoria (from the 6th lumbar, PI. VII, i6) crosses the ventral face of 
the A. glutea anterior, close to its origin from the iliaca interna. 

(6) A. circumflexa femoris lateralis (iliaco-femoral artery) is one 
of the terminal branches of the iliaca interna. To expose the vessel, draw 
aside the distal portion of the psoas magnus ; transect the iliacus and draw it 
aside. The artery crosses the shaft of the ilium a little dorsal to the in- 
sertion of the psoas parvus and enters the quadriceps femoris group of 
muscles between the rectus femoris and the vastus externus. It supplies 
branches to the psoas magnus and iliacus, rectus femoris, tensor fasciae 
latae, vastus externus and medius and the superficial and middle gluteal 
muscles. The artery is accompanied by two large veins. 

(7) A. obturatoria (PI. V, 38) is the inner terminal branch of the A. 
iliaca interna. It passes posteriorly on the inner or pelvic surface of the 
shaft of the ilium along the ventral border of the iliac portion of the M. 
obturator internus. The obturator vein and nerve accompany the artery. 
At the anterior border of the obturator foramen the artery, vein and nerve 
dip beneath the M. obtvirator internus (PL V, 18'). Cut the overlying 
portion of this muscle close to its origin and turn it aside. In its course 
beneath the M. obturator internus the artery gives off small twigs to it; 
also a larger branch which passes through the obturator foramen and is 
supplied to the hip joint. At the very posterior part of the obturator 
foramen the obturator artery gives ofif a small branch which passes posteri- 
orly on the dorsal surface of the ischimn, to the ischial arch, where it anasto- 
moses with a branch of the A. obturatorius that extends along the ventral 
face of the ischium; it also anastomoses by a small branch with the A. 
pudenda interna. The extrapelvic portion of the A. obturatoria is deeply 
covered by the muscles of the inner side of the thigh and can be only par- 
tially exposed at present. First dissect the M. gracihs, beginning at its 
posterior border; free it from the underlying muscles and at the same time 
transect it a little below its middle. Turn back the proximal portion 
of the muscle noting the blood-vessels and nerves that enter it. Now 
beginning at its posterior border, cut the muscle about two-thirds of the 
way across, close to its attachment to the pelvis, in order to expose clearly 
the origin of the adductor magnus. (The adductor magnus as here used 
includes the adductor parvus of some writers). Note the deep inguinal 
lymph gland 12 to 15 cm. in length, that lies in the space between the 



35 

sartorius and the pectineas (PI. V, 63). Note the relation of this gland 
to the large artery (A. femoralis) beneath it and to the inguinal ligament. 
Dissect between the pectineus and the £idductor magnus, on one side, and 
the deep inguinal lymph gland and the A. and V. femoralis, on the other. 
Transect the pectineus a little below its middle and draw aside the distal 
portion. Carefully remove any connective tissue or fat from the space 
between the pectinevis and the adductor magnus and find the small nerves 
that enter each of these muscles. Dissect between the adductor magnus 
and tlic semimembranosus; transect the adductor magnus close to its 
pelvic attachment and draw up the muscle sufficiently to expose the M. 
obturator externus which is directly beneath the proximal portion of the 
adductor magnus. Find the A. obturatoria (and large vein) where it emerges 
from beneath the posterior border of the M. obturator externus, close to 
the ventral surface of the ischium. The posterior portion of the M. 
obturator externus must now be cut close to its origin and drawn aside in 
order to expose the A. obturatoria, after it passes through the obturator 
foramen. About 5 cm. from the posterior edge of the foramen the artery 
gives ofif a large branch which runs along the ventral surface of the ischium 
to the ischial arch where it divides into several branches, of which one goes 
to the crus penis close to its attachment to the ischium. The extrapelvic 
portion of the A. obturatoria also gives off a branch to the ventral surface 
and one to the dorsal surface of the penis. About 5 cm. peripheral to these 
two branches a much larger branch is given off to the semimembranosus. 
Further dissection of the obturator artery must be deferred until the over- 
lying muscles have been dissected. 

N. obturatorius ( Pl.V, 49; PI, VII, 16) originates from the 4th and 5th lumbar 

nerves; frequently however, it receives a branch from the 6th lumbar 
nerve. The nerve extends directly to the anterior part of the obturator 
foramen. It lies just beneath the peritoneum and for some distance accom- 
panies the obturator artery and vein; the nerve and blood-vessels then 
diverge from each other, the nerve passing through the anterior part of 
the obturator foramen and the blood-vessels through the posterior part. 
Reflect the proximal portion of the M. gracilis and the large branch of the 
N. obturatoris that supplies it will be seen on the proximal portion of the 
muscle extending transversely toward its posterior border. Upon drawing 
aside the proximal portion of the M. pectineus the branches of the N. 
obturatorius to it and to the adductor magnus may be seen. Upon 
drawing the adductor magnus from the obturator externus the branch 
of the obturator nerve that passes through the M. obturator externus, 
near its anterior border, and enters the adductor magnus, may be seen. 



36 

Turn aside or remove a portion of the obturator externus and trace the 
respective branches suppHed to it and to the adductor niagnus, the gracilis, 
and pectineus to their respective places of origin from the obturator nerve. 
It will now be seen that N. obturatorius divides into two branches one of 
which is distributed to the gracilis and pectineus and the other to the 
adductor magnus and obturator externus. 

N. pudendus (PI. V, 57, 57') originates from the 2d and 3d sacral nerves, or in 
some cases from the 3d only. It extends posteriorly, at first on the inner or 
pelvic surface of the sacro-sciatic ligament, but gradually passes into the 
substance of the ligament. Near the lesser sciatic foramen the nerve 
crosses the lateral surface of the A. pudenda interna, (PL V, 37), and 
inclining inwards, turns around the ischial arch and gains the dorsal surface 
of the penis along which it continues as the N. dorsalis penis. vShortly 
before the nerve crosses the A. pudenda interna it gives off the N. haemor- 
rhoidalis medius, or perinaeo-anal nerve (PL V. 57") which is distributed 
by numerous branches to the muscles of the urethra and penis, including 
the ischio-cavernosus muscle, -and to the terminal portion of the rectum. 
The communicating branch of the posterior ventral gluteal nerve (PL V, 55) 
to the N. pudendus joins the latter at the place of origin of the perinaeo-anal 
nerve. In the female the N. pudendus is distributed to the labia, clitoris, 
and the constrictor muscles of the vulva and anus and to the perineum. 

N. hemorrhoidalis (PL V, 60) is formed from the 3d and 4th sacral nerves 
or from the 4th ,only. It passes posteriorly on the inner or pelvic face 
of the sacro-sciatic ligament to the anal region where it divides into a 
number of branches which are distributed to the retractor and sphinctor 
muscles of the anus and to the skin of the perineal region. 

A. profunda femoris arises either in common with the truncus pudendo- 
epigastricus (or prepubic) or a little peripheral to it. It passes caudo- 
ventrally between the pectineus and the terminal tendon of the iliacus 
and psoas magnus. Draw aside the pectineus and demonstrate the one 
or more small branches supplied to it. Beneath the adductor magnus the 
artery gives off a very large branch which is distributed to this muscle, and 
to the gracilis and the semimembranosus. It also supplies twigs to 
the deep inguinal lymph gland. The remaining portion of the A. profunda 
femoris is covered by muscles and cannot be traced at present. A large 
vein accompanies the artery. 

A. femoris anterior (Pl.V, 32) arises from the A. femoralis about 2 cm. peripheral 
to the femoris profunda, from the opposite side of the A. femoralis. It passes 



37 

anteriorly and enters the precural group of muscles between the rectus 
femoris and vastus internus. It supplies branches to the iliacus and the 
quadriceps femoris muscles. 

Exposure of the gluteal vessels and nerves. 

Remove the skin from the gluteal and femoral regions. Dissect be- 
tween the biceps femoris and the adjoining mviscles, viz., the gluteus superfi- 
cialis and vastus extemus, anteriorly, and the semitendinosus, posteriorly. 
Also dissect between the semitendinosus and the semimembranosus. Tran- 
sect the semitendinosus opposite the ischial tuberosity and draw aside the 
proximal portion just enough to expose the nerve and blood-vessels that 
enter it immediately dorsal to the ischial tuberosity (PI. IV, 25). Transect 
the biceps femoris at the level of the external small trochenter and also at the 
level of the nerve, just exposed, to the semitendinosus, i.e. immediately 
dorsal to the ischial tuberosity. In this latter transection one of the large 
nerve branches to the biceps femoris will probably be cut; the other large 
nerve branch to this muscle lies more deeply and may be seen readily if the 
proximal portion of the muscle be drawn aside. Trace both of these 
large branched peripherally for some distance. Upon drawing aside the 
proximal portion of the biceps femoris it will be seen that the two or three 
large branches just mentioned (and the A. and V. glutea posterior) emerge 
from beneath the gluteus medius and are distributed to the biceps femoris 
and also one small branch to the posterior border of the gluteus super- 
ficial is (PI. IV, 23). These large nerve branches cannot be traced at present 
to their place of origin from one of the posterior gluteal nerves. Now 
dissect between the tensor fasciae latae and the gluteus superficialis taking 
care not to cut the nerve or blood-vessels that emerge from beneath the 
anterior edge of the gluteus superficiahs near its middle, and enter the 
adjoining borders of the tensor fasciae latae and the gluteus superficialis 
(PI. IV, 22). Transect the gluteus superficialis a little proximal to the 
nerve just exposed, turn it aside somewhat, and note the small nerves and 
blood-vessels supplied to its anterior edge. The gluteus medius should 
now be transected a little proximal to the two above mentioned nerves 
that emerge from beneath the respective anterior and posterior borders 
of the muscle, i.e. the nerve to the tensor fasciae latae and the nerve to 
the biceps femoris (PI. IV, 22,23). The deep face of the gluteus medius is 
indicated by these two nerves and they shoidd be kept in view while transect- 
ing the muscle; this maybe done if while transecting it, the proximal portion 
of the muscle be freed largely from its attachment to the iliac fossa and the 
sacrum and turned back. Note the vein and artery — A. iliolumbalis — 
that cross the external border of the ilium from 5 to 8 cm. ventral to the 



38 • 

external angle of the ilium and are distributed to the gluteus medius and 
tensor fasciae latae. See p. 33. 

A. glutea anterior. The distribution of the A. glutea anterior to the mid- 
dle and deep gluteals may now be demonstrated. The artery will have 
been cut when the gluteus medius was turned back. Clean up the artery 
in so far as it can be traced. See p. 34. 

A. glutea posterior or ischiadicus (continued, see p. 33). The distribu- 
tion of the A. glutea posterior to the biceps femoris, the semitendinosus 
and, in this specimen, to the internal part of the gluteus superficialis, may 
now be demonstrated. 

Nn. glutei. There are 5 or 6 of these nerves which are usually described 
as the anterior and posterior gluteal nerves. 

Nn. glutei anterior. There are three or four nerves in this group. They 
pass through the great sciatic foramen and are distributed to the gluteal 
and other muscles as follows: one large nerve lying at the .anterior side 
of the N. ischiadicus passes postero-laterally across the dorsal surface of 
the shaft of the ilium and between the middle and deep gluteal muscles 
and is distributed to the tensor fasciae latae and the gluteus superficialis as has 
been already demonstrated (PI. IV, 22). Sometimes this nerve sends a 
small branch to the gluteus medius. A short distance from its origin it 
frequently gives one or more short branches to the gluteus profundus; 
a branch from this nerve is also sent to the M. capsularis. The other large 
anterior gluteal nerves have a very short course before entering ihe gluteus 
medius ; they arise from the lateral side of the plexus but are so completely 
hidden from view by the great N. ischiadicus that they are liable to be 
overlooked. They accompany the A. ghitea anterior through the great 
sciatic foramen and immediately enter the gluteus medius. 

Nn. glutei posterior (PI. V, 55, 56). There are two large nerves in 
this group, a dorsal or superior, and a ventral or iiiferior nerve, both of 
which apparently arise from the dorso-caudal side of the N. ischiadicus. 
The one first given oiT, the posterior dorsal gluteal (PI. V, 56), really has 
its origin from the 6th kimbar and the i st and 2d sacral nerves ; only a few 
fibres however come from the 6th. The nerve extends posteriorly between 
the sacro-sciatic ligament and the gluteus medius and upon emerging from 
beneath the latter muscle it extends between this muscle and the biceps 
femoris to which it is distributed as has already been demonstrated (PI. IV, 
23). One small branch from this nerve is sometimes supplied to the gluteus 



39 

medius and one to the posterior edge of the gluteus superficiaUs. The 
second posterior gluteal nerve, posterior ventral gluteal, originates from the 
1st and 2d sacral nerves but to a very slight extent however, from the 1st 
sacral. This nerve also passes posteriorly between the sacro-sciatic liga- 
ment and the M. gluteus medius. Eight or ten centimeters from its origin 
it divides into two branches of which one enters the semitendinosus im- 
mediately dorsal to the ischial tuberosity as already demonstrated (PI. IV, 
25). This branch of the posterior gluteal nerve gives off a filament that 
unites with the N. pudendus as already demonstrated. The other branch 
of the posterior ventral gluteal nerve emerges near the middle of the outer 
surface of the ischial tuberosity and may be seen between the biceps femoris 
and the semitendinosus, upon turning aside the latter muscle (PI. IV, 25'); 
it is distributed subcutaneously to the region just below the ischial tubero- 
sity. In addition to the gluteal nerves already mentioned there is given 
off from the N. ischiadicus another small nerve which extends nearly par- 
allel to the N. ischiadicus and is distributed to the M. gluteus profundus. 
Sometimes this small nerve originates from the gluteal nerve that supplies 
the tensor fasciae latae and the gluteus superficialis. 

A. profunda femoris (continued). 

Draw out the middle one of the three portions into which the biceps 
femoris has been cut and note the large A. profunda femoris (and veins) 
that enters the muscle a little above the level of the external small tro- 
chanter (PI. IV). Cut the vessels, turn back this portion of the muscle as 
far as possible and trace the artery to its distribution in the biceps femoris 
principally; small twigs are supplied to the gluteus medius, the quadratus 
femoris and the adductor magnus. 

A. obturatoria (continued). 

Remove piecemeal a portion of the semimembranosus and trace the 
artery to this muscle; one or more branches go to the semitendinosus and 
one to the biceps femoris. 

Nerves to the Mm. gemelli, obturator internus and quadratus femoris. 

Place the specimen with the gluteal region uppermost, clean up the 
N. ischiadicus (PI. IV, 26) and identify the following muscles — the gemelli, 
the tendon of the obturator internus and the quadratus femoris. The 
one or two small nerves that supply these muscles originate from the deep 
or internal face of the N. ischiadicus at nearly the same level as the posterior 
ventral gluteal nerve and lie between the N. ischiadicus and the sacro- 
sciatic ligament so that in order to see them the N. ischiadicus must be 



40 • 

drawn aside. Near the posterioi: border of the M. gluteus profundus the 
small nerve to the gemelli, etc., (in cases where only one nerve is present), 
gives off a small branch which passes through the lesser sciatic foramen 
into the pelvic cavity where it divides into two branches one of which 
extends anteriorly along the surface of the iliac portion of the M. obturator 
internus to which it is distributed; the other branch supplies the other 
head of the obturator internus (PI. V, 50). The main nerve itself crosses 
the deep or internal face of the gemelli and the tendon of the obturator internus, 
supplies branches to the gemelli and may be seen again at the posterior 
border of this muscle where it enters the adjoining quadratus femoris (PL 
IV, 27). Demonstrate this by carefully separating the adjoining borders 
of the gemelli and quadratus femoris in order to expose the nerve. The 
gemelli and the tendon of the obturator internus may now be transected 
in order to expose completely the nerve and its branches as above men- 
tioned. 

N. ischiadicus (PI. V, 54; PL IV, 26) arises from the 5th and 6th lumbar 
and the i st and 2d sacral nerves ; occasionally it receives a branch from the 
3d sacral nerve. It passes through the great sacro-sciatic foramen and 
between the sacro-sciatic ligament and the M. gluteus medius, crosses a 
portion of the gluteus profundus, the gemelli and the tendon of the obturator 
internus and the quadratus femoris. Near the level of the gemelli the 
N. iscMiadicus divides into two terminal branches — peronaeus communis 
and N. tibialis (PL IV, 29, 34). (It should be kept in mind that the N. 
ischiadictis and its branches are named differently by different authors. 
The names here given are the names used in the more recent text books of 
anatomy and are the terms recommended by the various National Ana- 
tomical Societies.) In the femoral region the Nn. peronaeus communis 
and tibialis are surrounded by the biceps femoris, the adductor magnus 
and the semimembranosus. Near the level of the gemelli there is given off, 
either from the N. ischiadicus or from the N. tibialis, a large fasciculus 
which extends somewhat posteriorly and supplies the biceps femoris, semi- 
tendinosus and semimembranosus (PL IV, 28). Demonstrate, by dissect- 
ing between the biceps femoris and the semitendinosus and between the 
semitendinosus and the semimembranosus. Transect the semitendinosus 
at the level of the 3d trochanter and trace the nerve branches to their 
respective muscles. 

N. peronaeus communis (PL IV, 29). The distal portion of the biceps 
femoris must now be turned aside, noting the blood-vessels, which must 
be cut, that enter the muscle and also the small nerve — peronaeal cutaneous 
(PL IV, 30, 30') — a branch of the N. peronaeus communis. This small 



41 

branch appears to go to the biceps femoris but in reaUty it passes through 
the muscle and is distributed subcutaneously to the external face of the 
tibial region. The large N. peronaeus communis is given ofif from the 
N. ischiadicus at the level of the gemelli muscle; it hes at the side of the 
N. tibialis until it reaches the M. gastrocnemius where it diverges from the 
N. tibialis and passes between the external head of this muscle and the 
biceps femoris (PL IV, 29). Beginning at the posterior border of the biceps 
femoris slit the tibial aponeurosis lengthwise the tibia and turn aside the 
aponeurosis and the distal end of the biceps femoris (PL IV, 10', 11'). 
Now trace the N. peronaeus communis to the place where, between the 
M. peroneus (or lateral digital extensor) and the extensor pedis, it dips into 
the anterior tibial group of muscles. Shortly before the nerve enters these 
muscles it divides into two terminal branches — the N. peronaeus super- 
ficialis and the N. peronaeus profundus (PL IV, 32, 33). The N. peronaeus 
superficialis is much the smaller of the two and is for the most part sub- 
aponeurotic. Near its origin it gives off a muscular branch to the M. 
peroneus or lateral digital extensor (PL IV, 32') ■ Trace the superficial or 
subaponeurotic portion of the nerve (PL IV, 32") to its place of distribu- 
tion near the middle of the metatarsus. Note the relation of the nerve to 
the extensor pedis, peronaeus and to the tibial aponeurosis. 

N. peronaeus profundus (PL IV, 33). Just as this nerve passes between 
the extensor pedis and peroneus it divides into several branches of which 
all but one are distributed to the extensor pedis and the tibialis anterior 
(PL VI, 34). Cut the extensor pedis below the middle of the tibia and draw 
it aside. The remaining branch of the peronaeus profundus lies deeply 
between the extensor pedis and the tibialis anterior (PL VI, 34')- In 
tracing this branch to its termination in the digital region the tendons of 
the extensor pedis and peroneus may be cut near the middle of the metatar- 
sus and drawn aside. As the nerve crosses the tarsus it gives off several 
small branches to this region and to the M. extensor digitalis brevis. At 
the tarsus the nerve divides into two main portions of which one accompanies 
the A. metatarsea dorsalis (lateralis) to the region of the fetlock (PL VI, 
35) ; the other portion of the nerve extends obliquely across the anterior 
face of the large metatarsal bone and may be traced as far as the fetlock 
and often even beyond that joint. 

N. saphenus externus arises from the N. tibialis at the level of the third 
trochanter (PL IV, 35; PL VI, 36). It extends along the postero-external 
part of the gastrocnemius, accompanied by a vein, to near the beginning 
of the tendo Achillis. At this point it occasionally receives a small 



42 

accessory branch from the N. peronaeus communis (PI. VI, 31). The N. 
saphenus externus then gains the interval between' the tendo AchiUis 
and the M. perforans and extends the length of this space, immediately 
beneath the tibial aponeurosis, accompanied by the V. saphena externa. 
Trace the nerve to its subcutaneous distribution at the outer face of the 
tarsal and phalangeal regions (PI. VI, 36). 

Demonstrate the popliteal Ijmiph gland, 6 cm. long by 2 cm. wide, in 
the space between the biceps femoris and semitendinosus immediately 
posterior to the gastrocnemius. 

N. tibialis is the larger of the two terminal branches of the N. ischiadicus 
(PI. IV, 34; PI. VI, 29). It lies beneath the biceps femoris until it reaches 
the gastrocnemius. Just as it passes between the two heads of the gastroc- 
nemius it gives off, anteriorily, a large fasciculus to the muscles on the 
posterior side of the tibia (PI. VI). To demonstrate the branches of this 
fasciculus carefully dissect up the external head of the gastrocnemius and 
transect it a little below the middle of its fleshy portion taking care not to 
cut the flexor perforatus which is partially embedded in the gastrocnemius 
(PL VI, II, II', 12). The Nn. saphenus externus and peronaeus communis 
shoi-dd also be left intact. The several branches of the fasciculus just 
mentioned should now be traced to their respective muscles, viz., one branch 
to the external head and one to the internal head of the gastrocnemius ; 
a somewhat smaller branch to the flexor perforatus. Transect the perfora- 
tus a little below the nerve supplied to it and draw aside the proximal part 
of the muscle. Trace the remaining branches of the fasciculus to the 
popHteus and flexor perforans (PI. VI). The N. tibialis passes between the 
two heads of the gastrocnemius and for a short distance runs along the 
posterior surface of the flexor perforatus; it then gradually crosses the 
inner face of this muscle and accompanied by a small artery, descends to 
the tarsus in the space at the inner side of the leg, between the tendo AchiUis 
and the flexor perforans. Place the leg with its inner or medial surface 
uppermost and expose the N. tibialis in this part of its course taking care 
not to injure the one or more small arteries that accompany the nerve. 
At the tarsus the N. tibialis divides into two terminal branches — the N. 
plantaris medialis and the N. plantaris lateralis. Note very carefully the 
relation of the N. tibialis to the internal saphena vein and artery and to the 
tibial aponeurosis. 

Nn. plantaris medialis and lateralis. These two nerves are the terminal 
branches of the N. tibialis. They follow the tendon of the flexor perforans 
through the tarsal sheath and, diverging somewhat from each other, descend 



43 

the metatarsal region on either side of the j^erforans tendon. Eaeh nerve 
is accompanied .by a slender artery (A. metatarsea plantaris superficialis) 
and by a vein. The N. plantaris lateralis gives off a branch of consider- 
able size to the proximal portion of the susix-nsorj' ligament. Near the 
middle of the metatarsus, the N. plantaris medialis gives off a branch that 
runs obliquely across the posterior face of the flexor tendons and joins 
the plantaris lateralis a little above the distal end of the rudimentary 
metatarsal bone. At the fetlock each plantar nerve divides into two or 
three branches which are identical with those of the thoracic limb. 

A. saphena. This sniall artery was noted when the N. saphenus intemus 
(p. 32) was dissected. The artery arises from near the middle of the A. 
femoralis. It extends along the inner or medial face of the thigh and leg 
to near the tarsus where it anastomoses (usually) with a small recurrent 
branch of the A. tibialis posterior. The artery is accompanied by the large 
V. saphena. 

A. femoralis. Turn aside the M. gracilis leaving intact the A. and V. 
saphena. Transect the semimembranosus a hand's breadth (10 cm.) from 
its attachment to the epicondyle of the femur and turn back the distal 
portion of the muscle. Now trace the A. femoralis from its origin at the 
level of the anterior border of the pubis to its termination just before it 
passes between the two heads of the gastrocnemius where it is continued 
by the A. poplitea. Note the muscles that are related to the artery, viz., 
the sartorivis, pectineus, vastus intemus and adductor magnus. Note 
also its relation to the deep inguinal lymph gland. 

Branches of the A. femoralis. 

(i) Pudendo-epigastricus or prepubic, see p. 29. 

(2) A. profunda femoris, see p. 36. 

(3) A. femoris anterior, see p. 36. 

(4) Rami musculares, to the vastus internus, sartorius, gracilis, adduc- 
tor magnus and semimembranosus. 

(5) A. saphena, see above. 

(6) A. nutritia femoris enters the nutrient foramen of the femur. 

(7) A. genu (articular branch). This small branch arises from the 
A. femoralis a little before the latter passes through the adductor magnus. 
It rtuis near the posterior border of the vastus intemus to the inner or 
medial surface of the femoro-tibial joint where it ramifies. It also gives 
small twigs to the vastus intemus and the adductor magnus. 

(8) A. femoris caudalis (or A. femoris posterior), is a large vessel which 
arises from the caudal or posterior face of the A. femoralis, just before the 



.44 

latter passes between the two heads of the gastrocnemius. Two or three 
centimeters from its origin the A. femoris caudaHs divides into two branches 
as may be seen upon turning aside the biceps femoris. (The external head 
of the gastrocnemius may be partially transected close to its origin from 
the femur.) One of the branches of the A. femoris caudalis passes upwards 
or proximally, a short distance (4 to 6 cm.) between the semimem- 
branosus and the biceps femoris and is distributed principally to the latter 
muscle; it also gives off two branches, in this specimen, to the vastus 
extemus. The other and larger branch of the A. femoris caudalis extends 
downward and backward close to the posterior margin of the internal 
head of the gastrocnemius and is distributed principally to the biceps 
femoris and semitendinosus ; small branches are also supplied to the gastroc- 
nemius and to the popliteal lymph gland. In the present specimen, about 
I cm. peripheral to the A. femoris caudalis a small artery arises which passes 
between the two heads of the gastrocnemius, immediately posterior to the 
flexor perforatus, gives small branches to that muscle and to the perforans 
and is continued as a slender vessel which accompanies the N. tibialis. 
It unites with a small recurrent branch of the A. tibialis posterior a short 
distance above the tarsus. In the present specimen, two additional arteries 
originate from the A. poplitea about 4 cm. peripheral to the A. femoris cauda- 
lis. The smaller of these two arteries goes to the external head of the gastroc- 
nemius; the larger one is distributed to the distal portion of the biceps 
femoris and the vastus extemus. The A. poplitea also gives off a small 
branch to the internal head of the gastrocnemius. All the above arteries 
are accompanied by veins. 

A. poplitea is the direct continuation of the A. femoralis. It runs between 
the tibia and the Mm. popliteus and flexor perforans as far as to the proximal 
part of the tibio-fibular or interosseous space where it divides into the A. 
tibialis posterior and the A. tibialis anterior. Cttt the M. popliteus a short 
distance from its origin on the external epicondyle of the femur and draw 
aside the muscle. Dissect between the M. peroneus and the flexor per- 
forans. Insert the finger beneath the portion of the flexor perforans that 
originates from the external tuberosity of the tibia and the adjoining portion 
of the fibula and identify the tibio-fibular space (see skeleton). Taking 
care not to injure the underlying artery, cut the perforans close to the 
external tuberosity of the tibia and the adjoining portion of the fibula; 
draw back the muscle and demonstrate the A. poplitea as mentioned above. 
It gives ofl: a branch that enters the intercondyloid space of the femur and 
supplies the femoro-tibial joint. 

A. tibialis posterior is the smaller of the two terminal branches of the A. 
poplitea. Begin the dissection of this artery near its peripheral end, i.e. at 



45 

its S shaped curve on the medial side of the leg, anterior to the tuber calsis. 
Turn back or remove the covering aponeurosis taking care not to cut the 
A. and V. saphena, draw aside the small internal head of the flexor perforans 
(M. flexor digitalis longus or flexor acessorius) and trace the artery as far 
as possible, without cutting muscles, towards its origin. Now returning 
to the origin of the artery, draw aside, and at the same time cut the flexor 
perforans from its attachment to the posterior face of the tibia svifficiently 
to expose the artery. 

Branches of the A. tibialis posterior. 

(i) Rami musculares to the Mm. popliteus and perforans. 

(2) A. nutritia tibiae enters the nutrient foramen of the tibia. 

(3) A. tarsea lateralis is a small branch which arises at the first flexure 
of the sigmoid portion of the tibialis posterior. It runs between the tibia 
and the flexor perforans and is distributed by several small branches to the 
tendon and the lateral surface of the tarsus. 

(4) One or more small branches from the convexity of the first ctu-ve 
of the sigmoid portion of the artery to the medial surface of the tarsus. 

(5) A. tibialis recurrens is a small artery which arises from the second 
convexity of the sigmoid curve of the A. tibilias posterior. It extends 
proximad along the N. tibialis and anastomoses with either the A. saphena 
or with a branch from the A. femoris caudalis that accompanies the N. 
tibialis. 

(6) A branch given off from the second convexity of the sigmoid curve 
passes between the tendo Achillis and the flexor perforans and is distributed 
to the tendon and the region of the tuber calsis. The A. tibialis posterior 
ends in two small terminal branches — the A. plantaris medialis and the 
A. plantaris lateralis. 

A. tibialis anterior. Dissect between the M. peroneus and the tibialis 
anterior and draw aside the latter muscle. The A. tibialis anterior is the 
larger of the two terminal branches of the A. poplitea. It passes through 
the proximal part of the tibio-fibular arch and descends, with two large 
veins, on the antero-lateral face of the tibia beneath the M. tibialis anterior. 
At the tarsus the artery gives off the A. tarsea perforans which passes 
through the tarsal canal and anastomoses with the two plantar arteries 
or sometines with only the plantaris externus to form the arcus plantarus or 
plantar arch. The trunk of the A. tibialis anterior is continued along the 
metatarsus as the A. metatarsea dorsalis (lateralis). The A. tibialis 
anterior supplies branches to the Mm. extensor pedis, tibialis anterior, and 
several branches to the tarsal joint. Near its middle the A. tibialis anterior 
gives off a variable branch — A. peronea — which descends along the fibula 



46 

under the M. peroneus to which it suppKes small branches; it also gives 
off a cutaneous branch. 

A. plantaris medialis and A. plantaris lateralis. 

These two small terminal branches of the tibialis posterior vary some- 
what in different specimens. The following disposition however is common. 
Each plantar artery descends with the respective plantar nerves, on either 
side of the perforans tendon, to the proximal part of the metatarsus where, 
between the flexor tendon and the suspensory ligament, they unite with the 
A. tarsea perforans to form the arcus plantaris or plantar arch. The flexor 
tendons should be cut and turned aside. Sometimes the A. plantaris 
medialis does not join the plantar arch but is continued as the small satel- 
lite vessel of the N. plantaris medialis. Four plantar metatarsal arteries 
originate from the plantar arch. The two small superficial arteries, meta- 
tarsea plantaris superficialis medialis and lateralis accompany the plantar 
nerves on either side of the flexor tendons and unite with the A. metatarsea 
dorsalis or with the corresponding digital arteries. Sometimes, as men- 
tioned above, one of the superficial plantar metatarsal arteries is the direct 
continuation of the A. plantaris medialis. Transect and draw aside the 
suspensory ligament. 

The two deep plantar metatarsal arteries, Aa. metatarsea plantaris 
profundus medialis and lateralis, descend between the suspensory ligament 
and the corresponding rudimentary metatarsal bones and unite near the 
fetlock with the A. metatarsea dorsalis. Of the two deep metatarsal 
arteries the medial or internal one is much the larger and supplies the 
nutrient artery to the large metatarsal bone. 

A. tarsea perforans arises from the A. tibialis anterior, passes through the 
tarsal canal and luiites with the plantar arteries or with the external one 
only, to form the plantar arch. 

A. metatarsea dorsalis (lateralis) is the direct continuation of the A. tibialis 
anterior. It crosses the anterior surface of the tarsal joint and descends, 
at first, in the oblique vascular groove on the lateral face of the proximal 
part of the principal metatarsal bone and then in the groove formed by 
the principal and the lateral rudimentary metatarsal bones. Near the 
distal end of the rudimentary metatarsal the artery passes between the 
two bones and divides on the posterior face of the principal metatarsal, 
between the two divisions of the suspensory ligament, to form the A. digitalis 
medialis and the A. digitalis lateralis. These two arteries and their branches 
are similar to those of the thoracic limb. 



PLATE IV 
LATERAL SURFACE 

1. External angle of ilium. 

2. Tuber ischii. 

3. External small or third trochanter. 

4. Lateral epicondyle of femur. 

5. M. obliquus abdominis extemus. 

6. M. tensor fasciae latae with posterior edge drawn aside. 

7. M. gluteus superficiaUs; (the gluteal apopeurosis has been removed). 

8. M. gluteus medius. 

9. M. gluteus profundus (in part.) 
10, 10', II, 11'. M. biceps femoris. 

12. 12'. M. semitendinosus. 

13. M. semimembranosus. 

14. Mm. gemelli. 

15. M. quadratus femoris. 

16. M. vastus externus. 

17. M. gastrocnemius. 

18. M. soleus. 

19. M. peroneus or extensor digitalis lateralis. 

20. M. extensor pedis or extensor digitalis longus. 

21. M. fle.xor peiiforans. 

22. One of the anterior gluteal nerves. 

23. Gluteal nerve to M. biceps femoris. 

24. Sacro-sciatic ligament. 

25. 25'. Posterior ventral gluteal nerve. 

26. N. ischiadicus. 

27. Nerve to the Mm. gemelli, obturator internus and quadratus femoris. 

28. Nerve fasciculus to the Mm. biceps femoris, semitendinosus and semimembranosus. 

29. N. peronaeus communis. 

30. 30'. N. peroneal cutaneous. 

31. Small filament to the femoro-tibial joint. 

32. N. peronaeus superficiaUs. 
32'. Nerve branch to M. peroneus. 

32". Superficial or subcutaneous branch of N. peronaeus superficialis. 

33. N. peronaeus profimdus. 

34. N. tibialis. 

35. N. saphenus extemus. 

36. Nerve filament to M. soleus. 





ir 



10 




< 30 



^ 



PLATE V 
MEDIAL VIEW. 



1-6. Lumbar vertebrae. 
I '-5'. Sacral vertebrae. 
I "-6". Coccygeal vertebrae. 

7. Pelvic symphysis. 

8. 8'. M. psoas parvus. 

9. M. psoas magnus. 

10. M. iliacus. 

11. 11'. M. sartorius. 

12. M. obliquus abdominis intcrnus. 

13. M. transversus abdominis. 

14. M. rectus femoris. 

15. M. vastus intemus. 

16. M. gracilis. 

17. Portion of prepubian tendon. 
18,18'. M. obturator intcrnus. 

19. M. sacro-coccygeus. 

20, 20'. M. compressor coccygcus. 
21,21'. M. retractor ani. 

22. M. retractor penis. 

23. M. recto-coccygeus. 

24. M. sphincter ani externus. 

25. M. sphincter ani intemus. 

26. Sacro-sciatic ligament. 

27. Aorta. 

28. A. mesenterica posterior. 
39. A. circumflexa iliaca. 

l.So. A. iliaca (of right side). 
30 ' Cut end of left A. iliaca. 

31. Truncus pudendo-epigastricus (prepubic artery). 

32. A. femoris anterior. 

33. A. femoralis. 

34. A. iliaca interna. 

35. A. sacrahs lateralis. 

36. A. glutea anterior. 

37. A. pudenda interna. 

38. A. obturatoria. 

39. A. umbilicalis. 

40. V. obturatoria. 

41. V. femoralis. 

42. Large vein in subpubic groove. 

43. V. pudenda externa. 

XVIII. Last thoracic nerve. I-VI. Lumbar nerves. 
I'-IV. Sacral nerves. 

44. Posterior mesenteric ganglion of the sympathetic ner\'e (just below 44). 

45. Sympathetic nerve trunk. 

46. 46'. N. femoralis. 

47. N. saphenus intemus. 

48. Branch of N. saphenus intemus to M. sartorius. 

49. N. obturatorius. 

50. Small nerve to the M. obturator intemus. 

51. Pelvic plexus. 

52. Anterior gluteal nerve to the Mm. tensor fasciae latae and gluteus superficialis. 

53. Nerve to the M. gluteus profundus. 

54. N. ischiadicus. 

55. Posterior ventral gluteal nerve. 

56. Posterior dorsal gluteal nerve. 

57. 57'- N. pudendus. 

57". N. dorsalis penis (of the left side) a continuation of the N. pudendus. 

58. Small nerves to the pelvic plexus. 

59. Branch of N. haemorrhoidalis to the M. retractor ani. 

60. N. haemorrhoidalis. 

61. Branch of N. haemorrhoidalis to the M. compressor coccygeus. 

62. Nerve branch to rectum. 

63. Deep inguinal lymph gland. 

64. External iliac lymph glands. 



r 



PLATE VI 
LATERAL VIEW OF PELVIC LIMB 

1 . External small or third trochanter. 

2. Lateral epicondyle of femur. 

3. Os calsis. 

4. Lateral rudimentary metatarsal. 
4'. Principal metatarsal. 

5. 5'. M. vastus extemus. 

6. M. adductor magnus. 

7. M. semimembranosus. 

8. M. semitendinosus. 

9. 10. M. biceps femoris (turned aside). 

11. 11'. Lateral or external head of M. gastrocnemius (transected and the distal portion turned aside). 
11". Medial or internal head of M. gastrocnemius. 

12. M. flexor perforatus (a short section has been removed). 

13. M. popliteus. 

14. M. flexor digitalis longus. 

15. M. soleus. 

16. M. flexor perforans. 

17. M. peroneus or extensor digitalis lateralis. 

18. M. tibialis anterior. 

19. M. extensor pedis or extensor digitalis longus. 

20. M. extensor brevis. 

21. M. interosseus lateralis. 

22. M. lumbricalis lateralis. 

23. 23', 23". Tibial and metatarsal aponeurosis. 

24. Suspensory or suprasesamoid ligament. 

25. Ligament of ergot. 

26. A. metatarsea dorsalis (lateralis). 

27. A. digitalis lateralis. 

28. V. digitalis lateralis. 

29. N. tibialis. 

30. N. peronaeus communis. 

31. Small branch from N. peronaeus communis to N. saphenus extemus. 

32. 32'. N. peronaeal cutaneous. 

33. N. peronaeus superficiaUs. 

33'. 33"- Muscular and cutaneous branches of N. peronaeus superficialis. 

34. 34'. N. peronaeus profundus. 

35. Branch of N. peronaeus profundus accompanying the A, metatarsal dorsalis (lateralis). 

36. 36'. N. saphenus extemus. 

37. N. plantaris lateralis. 

38. Communicating branch for the N. plantaris medialis to the plantaris lateralis. 

39. 40, 41. Anterior, middle and posterior branches of N. digitalis lateralis. 
42. Portion of N. digitalis in the dorsal groove of third phalanx. 



PLATE VII 

DIAGRAM OF THE LUMBO-SACRAL NERVE PLEXUS 

1-6. Lumbar vertebrae. 

I '-5'. Sacral vertebrae. 

I "-6". Coccygeal vertebrae. 

I-VI. Ventral branches of lumbar nerves. 

I'-V. Ventral branches of sacral nerves. 

I"-V". Ventral branches of coccygeal nerves. 

7. Gangliated nerve-trunk of the .sympathetic nerve. 

8. Ramus commmiicans. 

9. N. ilio-hypogastricus. 

10. N. ilio-inguinalis. 

11. N. spermaticus externus. 

12. N. cutaneous femoris lateralis. 

13. Branch to M. psoas parvus. 

14. N. femoralis. 

15. Branch to M. iliacus. 

16. N. obturatorius. 
17-20. Nn. glutei anterior. 

21. N. ischiadicus. 

22. Posterior ventral gluteal nerve. 

23. Posterior dorsal gluteal nerve. 

24. N. pudendus. 

25. Small nerves to the pelvic plexus. 

26. Ner\'e to the M. retractor ani. 

27. N. haemorrhoidalis. 

28. 29. Fourth and fifth sacral nerves. 

30. First coccygeal nerve. 

31. Nerve trunk formed by branches of the coccygeal nerves. 
32-36. Coccygeal nerves. 



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